In 2023, six new landmarks and one new historic district were designated in Washington. The DC Preservation League nominated two of these landmarks: Chevy Chase Savings Bank and Northeast Savings Bank. In January, Chevy Chase Savings Bank, co-sponsored with Historic Chevy Chase DC, was designated by HPRB. The bank, designed by Arthur B. Heaton and completed in 1921, has since been added to the National Register. In October, Northeast Savings Bank, co-sponsored with Capitol Hill Restoration Society, was added to the DC Inventory. The bank was designed in a Beaux-Arts style by B. Stanley Simmons and has been an important institution in the H Street NE commercial district since its construction in 1921.

In addition to these two banks, the DC Preservation League co-sponsored the nomination for the Old Swedish Ambassador's Residence on Nebraska Avenue NW. This Spanish Colonial Revival style property, which was designated in December, was designed by Arthur B. Heaton and completed in 1924. Following its use as a private residence, it housed the Swedish Ambassador to the US from 1950 to 2023.

The DC Preservation League also drafted and submitted to the National Register additional documentation for the Mary Church Terrell House, a National Historic Landmark in the LeDroit Park Historic District, and the Benjamin Ogle Tayloe House in the Lafayette Square Historic District. This documentation adds important information related to the Women's Suffrage Historic Context Study.

Throughout the year, these other properties were officially added to the DC Inventory: Smothers Elementary School (March), US Naval Observatory Historic District (May), Eastern High School (August), and Little Tavern Shop No. 27 (September). An amendment for an existing historic site was also approved: the Smithsonian's National Museum of Natural History (January). And this December, the National Archives Building became DC's 76th National Historic Landmark!