Correct Maps 1791-1840
The fact is that there are very few correct feature maps of the area prior to 1792 available. This is a topographic map that an artist has created of the DC area. You can see the 'ferry road' connecting the East Branch and Georgetown that would be transformed into Penn Ave (in blue in the next image).
This is the dotted line drawing that we are told accompanied a letter of August 1791 by L'Enfant to Washington. Note especially that Mass Ave (red) has been staightened. Go back to the top of the last page and compare this map to L'Enfant's first draft where Mass Ave is quite bent. If this is indeed a L'Enfant map, then it was he who straightened the avenue.
Compare the area in the red box with the other images on this page, then with those on the last page.
This is the 1818 Robert King map. The first thing that you will notice is that Mass. Avenue is straight in 1818 but that the first map image portrays it as bent. This means that the avenue was straightened at some point, by someone. The quote above about L'Enfant being angry because his name was not on the map and that Mass Ave had been straightened, makes it appear as if he was not the one who straightened it, but the dotted line map shows that he was.
We are told that when L'Enfant first saw Ellicott's version of his map that he complained that it had been altered. Arnebeck says that Ellicott was proud of the changes that he had made. It seems that a comparison of the dotted line map and the Ellicott map and the 1818 map should tell us a lot. We have already shown that the line map shows Mass Ave straightened.
All the maps on the previous page are planning maps that show the Tiber Creek filled in and replaced by the canal. As you can see, this hadn't been done in 1840.