Paladin Took II
The thirty-first Thain of the Shire was Ferumbras Took III, who was unmarried and left no heir. As such, the line of descent from the Old Took's third son Isumbras IV came to an end, and the descent moved on to the line of his fourth son, Hildigrim. So the Thainship fell on Hildigrim's grandson Paladin, who became Thain Paladin II.
At some point, it seems that Hildigrim or one of his descendants had moved a little away from the ancestral home of the Tooks at Great Smials. Paladin was a farmer who worked the lands around Whitwell - a village which, though it appears on no map, is known to have been close to Tuckborough in the western Green Hills.
When Lotho Sackville-Baggins attempted his takeover of the Shire, Paladin came into his own. As the legitimate Thain, he refused to accept Lotho's authority, and when Lotho's ruffians were found in the Tookland, they were hunted and shot. So the Tookland remained independent while Lotho and later Sharkey took over the running of the rest of the Shire. A hundred of Paladin's archers marched to the Battle of Bywater and helped to defeat Sharkey's Men, but Paladin himself does not seem to have been at the battle.
Paladin was married to Eglantine Banks, and together they had four children. The eldest three were daughters, Pearl, Pimpernel and Pervinca, but the youngest was a son. This was the famous Peregrin Took, who travelled with the Fellowship of the Ring, and would inherit Paladin's title to become Thain Peregrin I.