Ho Chi Minh City is the base for any visit to Cu Chi — the city is 40 km away and has accommodation, food, and onward transport for the whole country. Most visitors do Cu Chi as a day trip from HCMC rather than staying overnight in the district.
Tay Ninh, about 100 km north of Ho Chi Minh City, is sometimes combined with Cu Chi on a longer day trip. The main draw is the Cao Dai Great Temple — the headquarters of Caodaism, a Vietnamese syncretic religion founded in the 1920s that combines elements of Buddhism, Taoism, Confucianism, and Catholicism. The elaborate temple, with its noon ceremony conducted by white-robed worshippers, is unlike anything else in the country. The drive passes through the same flat, agricultural landscape as the Cu Chi district. Combining the two sites makes for a long day; some operators run combined tours.
Mekong Delta day trips from Ho Chi Minh City are a separate excursion entirely — south rather than north, and a different landscape of river channels, floating markets, and rice paddies. They are among the most popular HCMC day trips but have nothing to do with Cu Chi.