Authorities say 26-year-old Nael Romero was last seen around 6 p.m. swimming in the creek at a party he attended in northeast Montgomery County.
He was in the water with other people, but no one has seen him since.
First responders searched the area of the party and the creek. Crews returned to the area to search a second time, but did not find him.
Romero is 5' and 120 pounds with black hair and black eyes.
Anyone with information about his disappearance is asked to call the Montgomery County Sheriff's Office at 936-760-5800.