Somehow Brownstoner managed to obtain a map of the calendared first phase of the Park Slope Historic District expansion. Unclear how they got it; we have been unable to locate it on the LPC's website. Excerpt shown below; click here for the full version.
7th Street is at the top; 16th Street at the bottom; 7th Avenue is at the left. The existing historic district, designated in 1973, is outlined in blue. The proposed expansion, comprising over 500 buildings, is outlined in red:
Significantly, the LPC decided to include the entire west side of Bartel-Pritchard Square (actually a circle, at lower right), because of the way that side creates a kind of special "gateway" into 15th Street.