Monroe is a city in Snohomish County, Washington, United States. It is located at the confluence of the Skykomish, Snohomish, and Snoqualmie rivers in the Cascade foothills, about 30 miles (48 km) northeast of Seattle. Monroe’s population was 17,304 as of the 2010 census and was estimated to be 19,776 in 2019.

Monroe was originally founded in 1864 as the town of Park Place, located at the river confluence in the course of several existing settlements in the Tulaco Valley. The townsite was before a trading publicize used by the indigenous Skykomish people. Park Place was renamed to Monroe in 1890 to award U.S. President James Monroe, and was moved northeast to be near the tracks of the Great Northern Railway, which was build up in 1892. Monroe was incorporated in 1902 and was chosen as the house of a major abbreviated milk tree-plant and the acknowledge reformatory.

Monroe became a suburban bedroom community in the late 20th century, serving commuters to Everett, Seattle, and the Eastside. It is house to the Monroe Correctional Complex, which absorbed the original reformatory in 1998, and the Evergreen State Fair, which runs annually in late summer. The city is located at the junction of two highways, U.S. Route 2 and State Route 522, which were expanded in the late 20th century to sustain commuters.

The confluence of the Skykomish and Snoqualmie rivers had originally belonged to the original Skykomish tribe, who predominantly occupied the area between modern-day Monroe and Index. The confluence itself was known as Tualco (Lushootseed: squa’lxo), and a user-friendly Skykomish village named S’dodohobc acted as a trade post amid several Coast Salish groups. A remove settlement close modern-day Monroe was used by the S’dodohobc band of the Snohomish people. The land roughly speaking the confluence was cleared into a prairie and used to cultivate berries, hazelnuts, and other plants. The Skykomish were in the middle of the tribes to sign the Treaty of Point Elliott in 1855, effectively ceding their conventional territories, including the Tulaco and confluence areas.

The area around modern-day Monroe was surveyed by George B. McClellan and the U.S. Army Corps of Engineers during their expedition to locate a good enough pass for a railroad across the Cascade Mountains. The Treaty of Point Elliott was not fully ratified until 1859, but the first American settlers had already arrived and claimed squatters rights to homestead in the Skykomish Valley. Robert Smallman, an English immigrant, arrived in 1855 and was the first to homestead upon the land in this area modern-day Monroe. He was followed by Henry McClurg, an appointed county commissioner, who established in the area with his wife Martha in 1860. McClurg well ahead founded the deal of Park Place in 1864, on a site one mile (1.6 km) west of modern-day downtown Monroe. Two new settlers arrived in 1860: Salem Woods, who claimed a small prairie to the northeast of Tualco and was well along elected county sheriff; and Charles Harriman, a territorial legislator who approved in Park Place.