Wallingford Avenue and the Wallingford neighborhood are named for real estate developer John Noble Wallingford (1833–1913). Originally from Maine, he moved to Massachusetts, then Minnesota as a young man. He fought for the Union all four years of the Civil War, and later moved to California before coming to Seattle in 1888. He was a city councilman from 1889 to 1891 and also a police commissioner.
Wallingford Avenue N begins as the Wallingford Steps at N Northlake Way, just north of Gas Works Park. It then goes 1⅔ miles north from N 34th Street to Woodlawn Avenue N, just south of Green Lake. At the north end of Green Lake, it goes 1⅓ miles north from E Green Lake Drive N to N 105th Street at Mineral Springs Park. It picks up again at N 135th Street, just north of Ingraham High School, and goes ½ a mile to the northern city limits at N 145th Street. As with many other North Seattle avenues, the name continues on into Shoreline; its northernmost appearance is at the King–Snohomish county line at N 205th Street.