Traditionally, this title was seen as a stepping stone to the NWA World Championship. This is exactly what the title was for Lex. From 1987 - 1991, Lex was seemingly always either the U.S. Champion or the number one contender for it. Over an 874 day period, he was only without the title for 65 days. While champion, he was involved in a feud with Ric Flair for the NWA World Championship. In 1991, he vacated the title when he won the vacant NWA World Championship from Barry Windham. So i think Lex Lugar is the longest U S Champion.
bruno sammartino
The longest reigning monarch in Thailand is His Majesty King Bhumibol Adulyadej.
hatshepsut
Rameses
victoria
house of hanover
After Saint Peter, the longest reigning pope was Pope Pius IX who served for 31 years, 7 months and 23 days.
she was and still is the longest reigning queen!
Chris John
brock lesnar
Gillberg
hatshepsut