Ladd's Addition is an inner southeast historic district of Portland, Oregon, United States. It is Portland's oldest planned residential development, and one of the oldest in the western United States. The district is known in Portland for a diagonal street pattern, which is at odds with the rectilinear grid of the surrounding area. Roughly eight blocks (east-west) by ten blocks (north-south) in size (by reference to the surrounding grid), Ladd's is bordered by SE Hawthorne, Division, 12th, and 20th streets.