Beginnings: 1800-1850[edit | edit source]
Photos, l-r: Map 1804, First Baptist Church, Harris House, Square's west end 1849. Click each photo to enlarge.
The first settlements on the land that is now occupied by Public Square were made by Watertown’s first settlers, who built their first homesteads on the square’s west end. Hart Massey's homestead, built in 1800, stood on the site of the Paddock Arcade. Zachariah Butterfield settled on the site of the YMCA, and Henry Coffeen settled on the site of the Iron Block.The terrain of the square was rough, The west end was 15 feet higher than the eastern end, while a stream ran from approximately the area occupied by Clinton Street, through the square’s west end and emptying into the Black River . 
New settlements in Watertown quickened, and in 1805, the settlers deeded the near-useless hillside that is now the square for public use. The square, as well its surrounding streets (Court, Arsenal, Washington, Mill, Factory and State Streets) soon took on their present form. Building on the square began apace, with more and more settlers arriving in Watertown looking for economic opportunities. Construction was quick, and somewhat haphazard. Numerous buildings, mostly of timber, were crowded into the square and its adjacent streets.
Despite the continued building of timber structures, masonry buildings were erected early on. John Paddock's Block, built near the site of today's Arcade, was the square's first brick structure, built in 1815. The American House was built in 1827 on the site of today's Woolworth Building. The Harris House was built in 1828 on the site of today's Franklin Building, and The First Baptist Church replaced their wooden church with a brick one in 1846. Norris Woodruff built the Woodruff Block in 1849 on the site of the former Iron Block . These buildings were considered modern for their time, constructed entirely of masonry. The Woodruff Block also contained a tin roof, and was considered fireproof. Unfortunately, none of these “modern” buildings would survive May 13, 1849.
The Great Fire of Watertown began in the carriage barn behind the American House. The fire, aided by a strong wind, quickly engulfed Arsenal and then Court Street, destroying every building on both sides of both streets. The fire spread to the square, destroying the American House, Paddock Block and all of the buildings up to Stone Street. The “fireproof” Woodruff block stood for a time, but the intense heat and burning embers began to melt the tin roof, and a defect in the building’s cornice allowed fire to soon engulf the building. The block and every building up to the current Woodruff Professional Building were destroyed. Citizens fought the fire with vigor, to no avail. The fire Chief Norris Woodruff was said to have constantly rode his horse back and forth through the fire, trying to help citizens save whatever possessions they could. Businesses were throwing their goods into the middle of the square. The fire raged until the next day, when rain helped to put out the flames. On the eve of Watertown’s 50th birthday, half of Public Square lay in ruins. But it didn’t stay that way for long .
One aspect of the fire proved beneficial to the square. The enormous amounts of rubble cleared after the fire was used to fill in the deep depression that existed between the east and west ends of Public Square, a project which had been in slow progress since the 1830's. The leveling of the land on the square, and the massive rebuilding in the next decade are what gave the square its current, familiar form.