Chalmers moved his family to Texas in 1840 and settled first in La Grange and then in Austin. He held office for a time as secretary of the treasury for the Republic of Texas under President Mirabeau B. Lamar and later chaired the committee that drafted the resolution approving the annexation of Texas to the United States. Chalmers helped establish the Democratic party in Texas. In 1845 he became editor and proprietor of the Austin New Era. He also formed a partnership with Michael Cronican to publish the Austin Texas Democrat. On January 1, 1847, he became involved in a heated argument with Joshua Holden; a fight resulted and Chalmers was mortally stabbed. He was buried in Oakwood Cemetery, Austin.
30° 16.566, -097° 43.703