A portion of the Hosford-Abernethy neighborhood, Ladd’s Addition, is National Historic District. It received this dedication in 1988. With this district are a set of guidelines which are intended to maintain and enhance those qualities which make Ladd’s Addition a unique historic Neighborhood.
You can read the entire document here (it’s a 8.1 MB .pdf file, so please give it a moment to load):
Portland_Ladds_Addition_Design_Guidelines