The first primary source I used in search of the history of Washington DC was a newspaper page from Cheboygan, Michigan dated December 25th, 1884. The page can be found here.
The page offers, among several advertisements typical of the time, an invitation from the congressional commission of Washington DC inviting certain parties to the dedication ceremony of the Washington Monument. The monument had just been completed the year this advertisement was published, and this invitation provides a lot of insight into how big a deal the dedication of the monument was to the United States. The ad asks any “civil, military, and naval” organization that might like to attend the ceremony to contact the person in charge of the ceremony’s procession with the amount of people in their organization.
This source offers a lot of insight into the scale of the event that was the dedication of the Washington Monument, which is undoubtedly one of the most prominent events in DC’s history. However, this document is simply a window into a singular event in Washington’s history, and beyond that it offers little more than perspective on the event and some idea of the nation’s attitude towards the dedication of the monument.
The second primary source I examined was a map of Washington DC in 1909, which I found on the Library of Congress website. The map can be found here. This source offers a map of Washington in it’s entirety, with detailed depiction of streets, and a list of presidential inaugurations that had taken place there by 1909. The map is from Washington’s inaugural committee, so it also lists all members of the committee. This source is more than just a map in that it offers a list of many important figures during the time as well as which presidents had been inaugurated by 1909. It is a reliable depiction of Washington DC in 1909 and more so as far as a source on DC’s history goes it is quite a rich resource.
I prefer this second source to the first one due to the fact that it offers a much wider scope of information in a simple image than the first source does, despite the fact that the first source is a long text passage.