This link allows you to search for a notary public by address. Once you upload the map, simply key in any DC address, and the map will display icons resembling houses and building representing business and residential notaries. The name and contact information for the notary will appear; in the case of a business, there may be more than one notary at the address.
Please be sure to call or email the individuals in advance as notaries public are not required to notarize documents simply because they appear on this list.
You can also download the complete list at Open Data DC catalog.