[a][4] He moved to Washington around 1793 and was chosen by Benjamin Latrobe as his principal assistant on his project to build the United States Capitol in 1803.

His wife, Jane King, whom he married in either 1801 or 1802, was the daughter and sister of the surveyors of the District of Columbia.

Lenthall was killed in September 1808 when one of the arches in the Supreme Court chamber collapsed.

They were designed as a single unit and they share a common roof and cornice line.

The white wooden trim surrounding the doorways was changed in the second half of the nineteenth century.