[3] He was chairman of the Committee on Public Lands for the 14th and 15th United States Congresses.

[3] Following his departure from Congress, Robertson resumed private practice in Louisiana from 1818 to 1820.

[1] He was confirmed by the United States Senate on May 26, 1824, and received his commission the same day.

[1] He was interred in Copeland Hill Cemetery in White Sulphur Springs.

[4] In 1827, Robertson, along with Armand Duplantier, Fulwar Skipwith, Antoine Blanc and Sebastien Hiriart received permission from the Louisiana State Legislature to organize a corporation called the Agricultural Society of Baton Rouge.