The story
# The Texas city was named after George M. Dallas, vice president to Polk; family name is evolved from dalhous (13th c.), meaning "dweller at the house in the dale," from dale + house. # The Scottish place-name is from Pictish, equivalent to Welsh dôl (“meadow, haugh”) + gwas (“abode”).
Etymology from Wiktionary, CC BY-SA 4.0.