Armitage Avenue is an east–west street in Chicago and its western suburbs, being located at 2000 North in the Chicago address system, two and one-half miles north of Madison Street. Its west end is located at President Street in the western suburb of Glendale Heights. In the western suburbs, it is a minor road, being split into many segments, usually by freeways. Armitage Avenue becomes a major street at its intersection with Grand Avenue in Chicago, continuing east until Mendell Street, just east of its interchange with Interstates 90 and 94 (Kennedy Expressway), and just west of the North Branch of the Chicago River. Immediately east of the river, it resumes as a minor road, beginning at a cul-de-sac, heading east until Southport Avenue. At Racine Avenue, Armitage Avenue is once again a major street. From here, it continues east until its east end at Clark Street, just west of Lincoln Park.

Armitage Avenue begins at President Street in Glendale Heights. The road continues east for 2.1 miles (3.38 km) to Wayne Avenue.

The next two segments of Armitage Avenue are in Lombard. Armitage Avenue starts again at Swift Road and continues for 0.04 miles (0.06 km) before ending in a cul-de-sac. The next segment starts in a cul-de-sac and ends at Helen Street. This segment is 0.03 miles (0.05 km) long.

The next two segments are in Addison. Armitage Avenue continues at a cul-de-sac for 0.2 miles (0.32 km) and ends at Rohlwing Road. The road resumes at Addison Road and also goes through Villa Park for 0.9 miles (1.45 km) before stopping at Villa Avenue.

The following two segments of Armitage Avenue lies entirely within Elmhurst. The road resumes east of the Cricket Creek Forest Preserve at Garden Avenue, a frontage road of Illinois Route 83 (Kingery Highway). The road goes for 1.24 miles (2.00 km) until turning south as Addison Avenue. Armitage Avenue begins again at Indiana Street, continuing 0.31 miles (0.50 km) until turning north as Adele Street. The two segments in Elmhurst are split because of U.S. Route 20/Interstate 290 (Eisenhower Expressway).

Armitage Avenue's eighth and ninth segments are located in Melrose Park. It begins at Wolf Road in Northlake. One mile further east, it intersects U.S. Route 12/U.S. Route 45 (Mannheim Road). This segment, 2.02 miles (3.25 km) ends at 25th Avenue. The ninth segment begins at a cul-de-sac west of 19th Avenue, and continues 0.56 miles (0.90 km) until ending at a cul-de-sac east of George Street.

The tenth segment of Armitage Avenue is located in Elmwood Park and the city of Chicago. Beginning at 78th Avenue in Elmwood Park, it continues east for 1.50 miles (2.41 km) until Nashville Avenue in Chicago. Halfway between these two streets, Armitage Avenue intersects Illinois Route 43 (Harlem Avenue), the border of Elmwood Park and Chicago.

The eleventh segment of Armitage Avenue is located entirely within the city of Chicago, as are the remainder of the segments. It runs 0.22 miles (0.35 km) from Menard Avenue to a cul-de-sac just west of Central Avenue.