Nearby provinces are (clockwise, from the east): Bueng Kan, Sakon Nakhon, Udon Thani, and Loei.

The province is in the valley of the Mae Nam Kong (Mekong River), which also forms the border with Laos.

The First Thai–Lao Friendship Bridge, which connects the two countries, was built jointly by the governments of Thailand, Laos, and Australia, and was opened in 1994.

[7] In more recent years, Nong Khai has become a popular destination during the Buddhist Lent festival when mysterious balls of light, or Naga fireballs, rise from the Mekong River.

Synthesizing Buddhist and Hinduist ideologies, Buddhas, many-armed goddesses, a seven-headed Naga snake, and various human-animal hybrids dominate the site.

As of 26 November 2019 there are:[11] one Nong Khai Provincial Administration Organisation (ongkan borihan suan changwat) and 19 municipal (thesaban) areas in the province.

The non-municipal areas are administered by 48 Subdistrict Administrative Organisations - SAO (ongkan borihan suan tambon).

[12] It is the road and railway gateway to Laos's capital, Vientiane (25 kilometers (16 mi) upriver), on the north bank opposite the Thai town of Si Chiang Mai District.