During 1928 and 1929, Ho Chi Minh used the jungle around Nong Hang village as one of his bases to train soldiers and rally Isan's sizeable Vietnamese community for his resistance against the French occupation of Vietnam. This is a replica of his thatched-roof, mud-wall house, plus a big museum, which may be of interest if you are into recent Vietnamese history.
Bâhn lung hoh (Uncle Ho's House), as locals call it, is 10km from Udon. You can get nearby on sŏrng·tăa·ou 14 (13B, 30 minutes), which parks on Th Prajak across from Precha Night Market and runs west on Th Wattananuwong and south along Th Mukkamontri before heading out of town. It's a 750m walk from the signed junction.