Texas Local Government Code - LOC GOV'T § 71.032. Suit to Enforce Payment of Liability

(a) A county from which a new county has been created may sue to recover the new county's share of the original county's indebtedness. The suit may be brought in a district court of either county.

(b) If a suit is brought to enforce payment of the indebtedness created by the original county or of the excised territory's proportionate share of the indebtedness, the tax assessment rolls of the original county for the year in which the new county was created are conclusive evidence of the property remaining in the original county, the property in the excised territory, and the value of that property as of the date of the creation of the new county. However, if the new county was organized and made assessment rolls for the year in which it was created, those assessment rolls are conclusive evidence of the property in the new county and the taxable value of that property as of the date of the creation of the new county, and the assessment rolls of the original county for that year are conclusive evidence of the property remaining in the original county and the value of that property as of the date of the creation of the new county.