During surveys in 2009, we documented 23 invasive exotic plant taxa in the restored prairie at Herbert Hoover National Historic Site. The most widespread and abundant of the exotic plant species observed included sweetclover, reed canarygrass, and smooth brome. Prevalent mainly in the western half of the prairie, sweetclover was established on at least 0.8 acres. Reed canarygrass and smooth brome each covered a minimum of 1 acre.