Gresham ( /ɡrɛʃəm/) is a city located in Multnomah County, Oregon, United States immediately east of Portland. It was named for the American Civil War general, and Postmaster General, Walter Quinton Gresham. The population was 105,594 at the 2010 census. This makes Gresham the fourth largest city in Oregon.
The city of Gresham could not establish itself as a city unless given a post office and postal code. A local storeowner offered to use his store as a post office and offered to name the city after Postmaster General Walter Q. Gresham if a post office was granted. Until that time, the city had simply been known as Campground because this forested site was where pioneers often stopped to spend the night and compose themselves before moving on to Portland and the Willamette Valley. Although a post office was established in May 1884, Gresham was not incorporated as a city until 1905. Lewis Shattuck, son of a pioneer family, was the first mayor.
According to the United States Census Bureau, the city has a total area of 22.2 square miles (57.6 km²), of which, 22.1 square miles (57.4 km²) of it is land and 0.1 square miles (0.2 km²) of it is water. The total area is 0.40% water, which includes parts of Fairview Creek and Johnson Creek.