Adolphus Louis de Barth Walbach (November 1, 1764 – October 13, 1844) was a French-born Catholic priest in Pennsylvania and Maryland.
Born and raised in Alsace, France, he emigrated with his noble family to the United States during the French Revolution. He spent the rest of his life as a priest there, mostly at Conewago Chapel in rural Pennsylvania. After the Bishop of Philadelphia died in 1814, de Barth temporarily led the diocese as apostolic administrator until a new bishop arrived in 1820. After several years at a German-speaking Baltimore parish, he retired to Washington, D.C., in 1841 and died there three years later.