It runs from Woodward Avenue (Linden Hill Cemetery) in Ridgewood, Queens to Downtown Brooklyn, stopping at the Fulton Mall where the Dime Savings Bank and City Point meet. Between Woodward Avenue and Bushwick Avenue, DeKalb Avenue is a two-way, two-lane street; between Bushwick Avenue and Fulton Street, it is one-way westbound. (Lafayette Avenue is the corresponding parallel one-way street eastbound.) A bike lane, installed in 2004 and extended in 2008, exists between Malcolm X Boulevard and Flatbush Avenue.
Landmarks along the avenue include the Pratt Institute, Fort Greene Park, the Brooklyn Hospital Center, the DeKalb and Marcy branches of the Brooklyn Public Library, Long Island University's Brooklyn Campus, Brooklyn Technical High School, and Junior's.
Two New York City Subway stations serve DeKalb Avenue:
- DeKalb Avenue (B, D, N, Q, R, and W trains) on the BMT Fourth Avenue Line and BMT Brighton Line
- DeKalb Avenue (L train) on the BMT Canarsie Line
In addition, the following subway stations are within one or two blocks of DeKalb Avenue:
- Nevins Street (2, 3, 4, and 5 trains) on the IRT Eastern Parkway Line
- Lafayette Avenue (A and C trains) on the IND Fulton Street Line
- Fulton Street, Clinton–Washington Avenues, Classon Avenue, and Bedford–Nostrand Avenues (G train) on the IND Crosstown Line
- Kosciuszko Street (J train) on the BMT Jamaica Line
- Central Avenue (M train) on the BMT Myrtle Avenue Line