Past / Room 04 · Museum of Seattle
The Regrades
Between 1897 and 1930 Seattle moved more than eleven million cubic yards of earth into Elliott Bay. The new flat ground had a price—and property owners were expected to pay it.
About 3 min for the short read · 9 min for the full stories
Explore on the mapElliott Bay: then and nowWhat was left of Denny Hill, photographed by the City's engineers on 20 March 1929 — the year the final regrade began. The negative is marked "No. on 5th Ave Bet. Lenora + Blanchard." Apartment buildings already line the street, built hard against a cut face of the hill that was still waiting to go.
Courtesy of the Seattle Municipal Archives, #3582, Series 2613-07 (Engineering Department Negatives). · City of Seattle photograph; public record, no permission required. The item record names no other rights holder. · Archive record
Three things to notice
Seattle's flat ground was sometimes made by removing hills. Water jets, shovels, and conveyors changed grades so goods could move and lots could be developed. Property owners paid assessments, buildings disappeared, and expected growth did not always follow. This room asks you to read the terrain as a record of those decisions. It also revisits the familiar 'spite mound' story: the surviving evidence supports a more complicated account, including owners who lacked money to lower their land.
- Regrades changed the terrain to move goods and develop lots.
- Assessments and demolition imposed costs on property owners.
- The familiar 'spite mound' explanation exceeds the surviving evidence.
Read the room's argument
The regrades are usually remembered as engineering feats. But every project began with a petition and ended with an assessment. Owners faced the cost of the public work, interest, higher taxes, and a separate bill for lowering their own lots.
Many could not afford the result. The important calculation was therefore not only how much earth could be moved, but which households could remain after the ground—and its value—changed.
The man who disliked the topography
R. H. Thomson, city engineer, and the two things that made his plan possible.
The main idea, apparently, was to sell the lots
City engineer R. H. Thomson reshaped Seattle's terrain over a generation. Regrading served transportation and development ambitions; this panel examines the relationship between engineering decisions and the value expected from city lots.
Checked against the cited sources on July 28, 2026.
Read the full story
Reginald Heber Thomson arrived in Seattle in the early 1880s, became city surveyor in 1884 and city engineer in 1892, then spent a generation reshaping the city.
His diagnosis appears in the 1908 Annual Report. Seattle's founders, he wrote, had platted the land "with but little regard as to whether the streets could ever be used or not, the main idea being, apparently, to sell the lots."
Seattle's earliest claims and plats produced durable boundaries, including the seam that became Yesler Way. Here the city's own chief engineer states the consequence: much of the grid was drawn to sell land, not to follow usable grades, so the ground would be changed to fit it.
His remedy was equally direct. "Seattle was in a pit," he later wrote, "that to get anywhere we would be compelled to climb out if we could."
“with but little regard as to whether the streets could ever be used or not, the main idea being, apparently, to sell the lots”
Sources & evidence · 2
- ReferenceHistoryLink Essay 21204 — Denny Regrade (Seattle)— Thomson city surveyor Aug 1884, city engineer 1892; Annual Report 1908 quotation; "Seattle was in a pit" from his autobiography That Man Thomson
- ReferenceHistoryLink Essay 7045 — Seattle's Early Donation Land Claims— the claims the plats were laid over
Why water was enough
Seattle's glacial soils could be cut by pressurized water. Hydraulic regrading turned hills into movable earth, allowing engineers to change street grades at a scale that would have been harder in solid rock.
Checked against the cited sources on July 28, 2026.
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Seattle's hills are largely glacial clay, sand, cobbles, and boulders rather than solid bedrock. Engineers could therefore cut them with water under pressure.
A hydraulic giant—an articulated nozzle operated by a crew—turned hillsides into slurry. On Jackson Street, water emerged at about ninety pounds per square inch and a crew could move roughly a thousand cubic yards in an eight-hour shift.
The city's drinking water was not used to wash Denny Hill away. On the Jackson Street job, only about a quarter of the water came from the Cedar River supply; the rest was pumped from Elliott Bay and Lake Washington.
Sources & evidence · 2
- ReferenceHistoryLink Essay 21204 — Denny Regrade (Seattle)— glacial geology and the three-layer cake; the hydraulic giant and its five-man crew; ~1,000 cubic yards per eight-hour shift; "On Denny Hill none was used, with only about one quarter of the Jackson Hill water coming from the Cedar River"
- ReferenceHistoryLink Essay 23118 — Jackson Street Regrade (Seattle)— roughly 90 pounds per square inch; giants operated by men with Alaska goldfield experience
Denny Hill, five times
Two hundred and twenty feet of hill, removed in five separate projects across thirty-three years.
What was on the hill
Denny Hill once covered roughly sixty-five blocks. Its hotels, homes, and slopes occupied ground now read as ordinary downtown streets. Dated accounts help reconstruct what the flattening removed from that landscape.
Checked July 28, 2026 — with a caveat
The building counts are HistoryLink's, attributed in its text to an unnamed "Raymond thesis" that has not been traced. Treat 389 dwellings as a well-sourced order of magnitude rather than a census.
Read the full story
Denny Hill covered about sixty-five city blocks — a little over two hundred acres — roughly between 1st Avenue, Westlake, Pike and Broad. It topped out around 220 feet, half the height of Queen Anne or Capitol Hill, with its northern summit at 4th and Blanchard.
It was not empty. A survey of the area in 1893 counted at least 320 single-family homes and 69 multi-family buildings, along with 26 stables, 218 sheds and 10 hotels.
That is 389 buildings of housing—a figure often missing when the regrades are remembered mainly as quantities of earth.
When the last of the hill went in 1930, the Seattle Times described what had been cleared as "ill-kept streets, run-down residences, aged public and semipublic structures." That is the era's own account of what it thought it was removing.
Sources & evidence · 2
- ReferenceHistoryLink Essay 21204 — Denny Regrade (Seattle)— ~65 blocks and a little over 200 acres; original elevation ~220 feet; northern summit at 4th and Blanchard; 1893 counts of 320 single-family and 69 multi-family homes, 26 stables, 218 sheds, 10 hotels (Raymond thesis); Seattle Times "run-down residences" quotation
- ReferenceHistoryLink Essay 1123 — Seattle Neighborhoods: Belltown-Denny Regrade — Thumbnail History
Ten years at six percent
Owners petitioned for regrades and paid assessments through improvement districts. The cost depended on estimates of property gains and losses. Engineering the city also meant deciding who would finance its changes.
Checked against the cited sources on July 28, 2026.
Read the full story
A regrade required a petition from at least half the affected residents. Ordinances then defined the work and financed it through a Local Improvement District, charging owners according to an appointed panel's estimate of each property's gain and loss.
The problem was not really the process. It was what came after it. Homeowners had ten years to repay their assessment at six percent interest. They also owed tax on the new, higher assessed value of the land. And they owed the contractor, separately, for lowering their own property.
HistoryLink summarizes the result plainly: many could not afford the payments.
The arithmetic resembles a development pro forma—cost, increase in value, financing term, interest, and carrying costs—but imposed across a neighborhood. The households for whom the numbers did not close still had to absorb the change.
Sources & evidence · 1
- ReferenceHistoryLink Essay 21204 — Denny Regrade (Seattle)— 50 percent petition threshold; petition filed 28 April 1906; Ordinance 13776 signed 23 May 1906; Ordinance 14993 and the Local Improvement District, first used 1893; the assessment commission of two lawyers and an engineer; "Homeowners had 10 years to pay back their assessments at a rather steep 6 percent interest"; "Many could not afford to make these payments"
The spite mounds are a myth
The isolated Denny Hill lots became known as 'spite mounds.' Surviving evidence does not support that simple explanation; at least some owners described an inability to pay for lowering their ground.
Checked against the cited sources on July 28, 2026.
Read the full story
Six isolated buttes remained above the flattened hill in 1910. Seattle later called them "spite mounds" and told stories of owners refusing to cooperate, sometimes reaching their houses by ladder. The surviving record does not support that account.
As far as the records show, none of the five owners opposed the regrade. Zachariah Holden told a reporter he did not have the money to lower his lot; he later borrowed it. James Kelley, owner of two mounds, had been away when the contractor sought permission and rejected the accusation of spite when he returned.
The famous photographs appear to record financial constraint and project timing, not stubbornness. A century of retelling turned that hardship into a civic joke.
“I want to see every vestige of these hills come down. [I] would have been willing to make greater sacrifices to see Seattle become greater still”
Sources & evidence · 1
- ReferenceHistoryLink Essay 21204 — Denny Regrade (Seattle)— six mounds, five owners, May 1910; "As far as the records show, however, none of the owners were against cutting down Denny Hill"; Holden could not afford the work and later borrowed it; Kelley in the Klondike, both mounds gone by January 1911; "Nor is there evidence for another common urban belief, that homes were left on the mounds"
Many moist eyes
The earlier Denny regrade did not bring immediate development. A final project beginning in 1929 used shovels, conveyors, and self-dumping scows. The gap between the projects complicates a simple story of progress.
Checked against the cited sources on July 28, 2026.
Read the full story
The fourth regrade finished in 1911, but little development followed for seventeen years. The final project began in 1929, using electric shovels and conveyor belts instead of water. Self-dumping scows carried the earth into Elliott Bay.
On 10 December 1930, Mayor Frank Edwards took the ceremonial last scoop. Hundreds watched, including people born and schooled on the hill. "There were many moist eyes," a reporter wrote.
The final regrade moved 4,354,625 cubic yards and cost $2,261,800. Across all five projects, 11,112,025 cubic yards of Seattle went into the bay — most of it, on HistoryLink's account, unused for any purpose.
Not all waste. The third regrade's spoil was carried off on a small steam railway and dumped around Pine and Olive, which is the gentle slope that now runs up past the Paramount towards Capitol Hill. If you have walked it, you have walked on Denny Hill.
Sources & evidence · 2
- ReferenceHistoryLink Essay 21204 — Denny Regrade (Seattle)— regrade declared done 20 June 1911 and a 17-year pause; Nickum's self-dumping scows; Mayor Frank Edwards 10 December 1930; "There were many moist eyes"; 4,354,625 cubic yards and $2,261,800 for the fifth regrade; 11,112,025 cubic yards total; the third regrade's spoil dumped at Pine and Olive
- ReferenceHistoryLink Essay 711 — Seattle's Denny Regrade is completed after 32 years on December 10, 1930
The other hill
The largest single hill ever taken down in Seattle — and the bill nobody would pay.
Six hundred condemnations
Steep Jackson Street grades made horse-drawn freight expensive. Regrading required extensive condemnation and changed a ridge joining First and Beacon hills. The transportation gains came with the removal of existing buildings.
Checked against the cited sources on July 28, 2026.
Read the full story
Jackson Street Hill ran from Washington Street to Lane and from 6th Avenue S to 12th, part of the ridge joining First Hill to Beacon Hill. Its streets reached grades of nineteen percent, and hauling goods up them could cost five times what it cost on the flat, because the work was still done by horses.
Property owners petitioned in October 1905 and the council passed the authorising ordinance on 8 February 1906. Then the city ran into the fact that much of the hill was privately owned, and had to condemn it.
For six weeks in 1906, a Seattle jury heard six hundred condemnation suits and returned a verdict in every case. Many ratified negotiated agreements; others were bitterly contested.
Six hundred cases give the project a human scale. Alongside the cubic yards were an ordinance, a condemnation docket, an assessment roll, and hundreds of individual properties.
Sources & evidence · 1
- ReferenceHistoryLink Essay 23118 — Jackson Street Regrade (Seattle)— hill from Washington to Lane, 6th to 12th Avenue S; grades as steep as 19 percent and up to fivefold shipping costs; petition October 1905; ordinance 8 February 1906; jury heard 600 condemnation suits from 11 September to 26 October 1906, six days a week
Six dollars a foot
Jackson Street owners agreed to one assessment and faced a higher levy. Their dispute shows the financial stakes beneath the engineering story: anticipated benefits and actual costs could be very different.
Checked against the cited sources on July 28, 2026.
Read the full story
When the owners signed the Jackson Street petition they agreed to an assessment of six dollars a foot. When the city actually levied it, the figure came out nearer nine.
Owners sued, and in 1908 the Washington Supreme Court invalidated the assessment. Many then refused even the original six-dollar figure, depriving the city of money needed to pay the contractor. Work stopped with the job about 70 percent complete.
Enough owners later returned to the original rate for construction to resume, but fewer than half had committed by spring. The work finished with a quarter-million-dollar deficit still unresolved.
The lesson the record actually teaches is not that the owners were unreasonable or that the city was crooked. It is that a public work financed by charging its beneficiaries depends entirely on the estimate being right, and the estimate was out by fifty percent.
Sources & evidence · 1
- ReferenceHistoryLink Essay 23118 — Jackson Street Regrade (Seattle)— agreed assessment $6 per foot, levied nearer $9; Washington Supreme Court ruled the assessment invalid November 1908; Lewis & Wiley walked off 10 January 1909 at ~70 percent complete; work resumed 8 February; quarter-million-dollar deficit
The horses it was for
Lower grades on Jackson and King streets made hauling easier after millions of cubic yards were removed. The work was accepted in 1910, leaving a changed terrain for later neighborhood growth.
Checked against the cited sources on July 28, 2026.
Read the full story
By the end, Jackson Street's grade had come down from as much as seventeen percent to five, and King Street's from nineteen and a half to six. About 3.35 million cubic yards were moved. The Board of Public Works accepted the job on 8 March 1910. It remains the largest single hill ever removed in Seattle.
The work killed people. A hose operator dropped his nozzle and it whipped round and struck him. Another man drowned in the flume that drained the pit. A worker thawing dynamite over an open flame set it off and killed a nine-year-old boy standing nearby.
The engineering premise weakened almost immediately. The case for the Jackson Street regrade centered on the difficulty of hauling freight by horse. Motor trucks arrived within the decade and substantially reduced the cost of moving goods on steep grades.
The regraded district became the western part of Chinatown and later the Chinatown-International District. Yet the specific transportation problem that justified thirty months of work and cost three lives was soon being addressed by a different technology.
Sources & evidence · 2
- ReferenceHistoryLink Essay 23118 — Jackson Street Regrade (Seattle)— Jackson Street grade reduced from as much as 17 percent to 5, King Street 19.5 to 6; ~3.35 million cubic yards; accepted by the Board of Public Works 8 March 1910; the three fatalities; "Ironically, the automobile was gaining traction by 1910… By the 1920s, trucks had significantly reduced the problem of high shipping costs on steep hills"
- ReferenceHistoryLink Essay 23149 — Dearborn Street Regrade (Seattle)
Reading it on the ground
Two places where the regrades are still visible, one of them on this website.
The city under Pioneer Square
Street grades changed after the 1889 fire, before Thomson's largest projects. The spaces now called Seattle's Underground emerged from rebuilding at different levels. The panel marks where its source support remains thinner.
Checked July 28, 2026 — with a caveat
The July 1889 decision, the one-to-thirty-five-foot range and the 1892–1900 sidewalk rebuilding were assembled from SAH Archipedia and search results, not from a HistoryLink essay body read in this pass. The figures are consistent across sources but no single source read here carries all of them.
Read the full story
Seattle began changing street grades before Thomson's major projects, in the aftermath of the 1889 fire.
A month after the Great Fire, Seattle decided to raise nearby streets by as much as thirty-five feet. Retaining structures held the fill while new roadways and sidewalks were built above the old grade, leaving rebuilt ground floors and passages below. That remnant became the Seattle Underground.
It is the clearest thing in the city about what a regrade is: not the removal of a hill, but the decision that the ground is at a different height now, taken by ordinance, with everything already built on it left to cope.
Sources & evidence · 2
- ReferenceHistoryLink Essay 5115 — The Great Seattle Fire destroys much of the city's commercial core and waterfront on June 6, 1889— the fire and the rebuild that preceded the street raising
- SecondaryPioneer Square-Skid Road National Historic District — SAH Archipedia— street grades raised from one to 35 feet, deepest at 3rd Avenue S and Jackson; old sidewalks became areaways
The flat ground is a document
The map's contours describe terrain measured by City LiDAR in 2016. Reading them alongside historical accounts can reveal changed ground. This comparison is an interpretation, with limits distinct from a measured historical surface.
Checked July 28, 2026 — with a caveat
The contour source and layer behaviour are checked against this repository, not against an external authority. The reading of the contours north of Pike is an observation about our own map, offered as such.
Read the full story
The map's Topography layer draws the City of Seattle's 2016 LiDAR contours—index lines every fifty feet, with ten-foot lines appearing as you zoom in.
North of Pike Street those lines go quiet, and stay quiet across sixty-five blocks. That silence is not terrain. It is eleven million cubic yards of removal, five contracts, two ordinances, an assessment roll and, in 1893, three hundred and eighty-nine buildings of housing.
Slope affects excavation, access, drainage, and whether some housing forms fit at all. Much of Seattle's flat central land is flat because the city paid to make it so—and billed the people who stood on it.
The quiet contour lines are therefore not neutral terrain. They record contracts, assessments, displaced buildings, and deliberate decisions about the ground.
Sources & evidence · 2
- PrimaryCity of Seattle — 2016 LiDAR contours (the Topography layer on this site)— Seattle Open Data; ingested by this project's own pipeline — see src/scripts/ingest-contours.ts
- ReferenceHistoryLink Essay 21204 — Denny Regrade (Seattle)— 11,112,025 cubic yards across five regrades
Help tell this story
Open review task
Help locate primary records about the isolated Denny Hill lots in D·05: an assessment, petition, or owner's account. Give the document date and page so the story can be checked.
Panel source checks describe our reading of the cited material. They do not imply approval or endorsement by a community.