Tex. Local Government Code § 292.002

(a) The commissioners court of a county may provide an office building or a jail facility at a location in the county outside the county seat in the same manner that is applicable to such a building or facility at the county seat. The commissioners court may provide for the building or facility through the issuance of bonds as provided by Subtitles A, C, and D, Title 9, Government Code, or through the issuance of other evidences of indebtedness in the same manner as bonds or evidences of indebtedness applicable to a courthouse or jail at the county seat. The commissioners court may provide office space in the building or facility for any county or precinct office. However, a county officer who is provided space in the building or facility shall maintain an office at the county seat and shall keep the original records of office at that office unless otherwise required during a disaster, as defined by Section 418.004, Government Code.

(b) The commissioners court may authorize places located in the county but outside the municipality designated as the county seat as auxiliary courts for the holding of court proceedings and may designate those places as auxiliary county seats for this purpose.