Isaan (อีสาน; also Isan, Isarn and even Esarn) is Thailand's largest region, consisting of 20 provinces. Despite having 30% of Thailand's population, this region receives less than 3% of Thailand's tourist dollars. It is a multicultural region where Laos, Cambodia and Thailand meet, and has a rich history and great food. In particular, it is home to Thailand's second-largest ethnic group, the Thai Lao.

Regions

Cities
1 Khon Kaen — the "most Isaan" city in Isaan, this university town has nightlife and great food
2 Loei — known for its numerous high hills, mountains and is one of Thailand's vineyards
3 Nakhon Phanom — bordering Laos along the Mekong
4 Nakhon Ratchasima (Korat) — the chaotic hub of Isaan, gateway from central Thailand
5 Nong Khai — gateway to Vientiane and the lovely Mekong Valley
6 Roi Et — home to the tallest standing Buddha image of the world, Phra Phuttha Rattana Mongkhon
7 Surin — known for its annual elephant parade and Khmer temples
8 Ubon Ratchathani — almost always shortened to simply "Ubon", gateway to the Cambodia-Laos border
9 Udon Thani — this expat haunt is best known for the archaeological site Ban Chiang
Other destinations
1 Khao Yai National Park — Thailand's first national park and a UNESCO World Heritage Site
2 Phanom Rung Historical Park — beautiful Khmer temples and one of the top attractions in Isaan
3 Phimai Historical Park — some of the most important Khmer architecture in Thailand

Understand
Isaan is an up-and-coming region of Thailand which is very different to the rest of the country. It is flat, sparsely populated, and has few of the typical Thai tourist attractions like backpacker haunts, temples and beaches. Besides tourists, it attracts students and expats with its university towns, culture, food and nightlife. Its cities in particular have a certain energy that is hard to describe, but must be experienced.

Climate
Northeast Thailand is monsoonal, cool in the dry months of December and January, getting hot and humid in February, March and April, the very wet and tropical during May, June, July and August. Temperatures during the dry can be 25-30°C during the day and as low as 10°C overnight. For much of the rest of the year expect 30-35°C and high humidity. The air during February, March and April can be very smoky when the main cash crop of sugar is burnt to remove leaves and debris prior to cutting. Use the AQI website for more information and real-time air quality data.
Gepography
The region consists mainly of the dry Khorat Plateau which in some parts is extremely flat. Unlike the more fertile areas of Thailand, the northeast has a long dry season, and much of the land is not very fertile and grows only sparse grasses The plateau is bounded by the Mekong to the north and east, with mountains to the west and the south. Due to the region's poor soils, sticky rice became the staple food grown here, which thrives in flooded, poorly drained paddy fields. Cash crops like sugar cane and manioc are also commonly grown.

Talk
The native language of the inhabitants of the region is Isan, which is a dialect of Lao. Most inhabitants of Isaan are fluent in Thai.

Get in

By car
One of the best ways to enter the region is by car. Distances are long and the area is flat, so travelling by car is comfortable and convenient, if pricier than other options.

By plane
There are airports in Khon Kaen, Nakhon Phanom, Roi Et, Sakon Nakhon, Ubon Ratchathani, and Udon Thani. A flight to Khon Kaen from Bangkok will take you about an hour.

By bus
Isaan has a large and extensive public bus network. 
Depending on traffic, a bus ride to Nakhon Ratchasima from Bangkok takes about four hours. 
You can purchase bus tickets at a local bus station or online.
By train
Regular train services connect Bangkok with Ubon Ratchathani (via Nakhon Ratchasima, Buriram, Surin, Si Saket and other stations along the way) and Nong Khai (via Khon Kaen, Udon Thani, etc).

Get around
Depending on where you're coming from and where you want to get to, buses, minibuses, songthaews, motorbikes, and bicycles are all good options.
The train system is also a good way to get around, but with only two lines in the region, the number of locations served is limited.

See

There are many attractions in Isaan:

The surreal statues of Sala Kaew Ku, Nong Khai
The temple inside the mountain at Chiang Khan
The temple of beer bottles in Si Saket
The beautiful Khmer temples in the Phanom Rung Historical Park
Phimai Historical Park has even more Khmer architecture
Flora, fauna, and waterfalls in the Khao Yai National Park

Do
Listen to local mor lam music. The best nightlife is in Buriram and Khon Kaen. Isaan people have a reputation for going out every night of the week!

Eat
Isaan cuisine shares much in common with Lao cuisine, and is distinctly different from central Thai cooking, although there has been a considerable amount of cross-pollination. Perhaps the best-known Isaan dish is som tam (or tam mak hung in Lao/Isaan), a spicy salad prepared from unripe papayas. While Thais prepare this with dried shrimp, in Isaan the preferred style is with preserved crab (puu) or mudfish, an acquired taste. Other characteristic dishes include roast chicken (kai yaang), sticky rice (khao niaw), fermented pork and rice sausage (sai krok) and a wide variety of cold meat, mint and lemon juice "salads" known as larb.
Isaan cuisine is gaining in prestige and popularity: the Michelin Guide even began covering Isaan in 2023!
A word of warning: Isaan food is known, even among Thais, for being fiery hot.

Drink
In addition to the regular standbys, popular drinks in the Isaan region include lao kao, a strong clear spirit distilled from rice, and a home made fermented rice wine called lao hai (เหล้าไห), also known as sato or sa tho (สาโท), made from sticky rice in earthenware jars and drunk directly with a straw. Another popular spirit is Hong Tong, made from distilled molasses (making it a type of arak) and drunk with ice and soda.
Beware that distilling at home is illegal in Thailand, and while this is rarely enforced, it does mean that there is little if any quality control on the local moonshine.

Stay safe
Violence occasionally flares up along the Cambodian border, mainly near Preah Vihear, as Cambodia and Thailand squabble over a small patch of disputed territory. However, as elsewhere in Thailand, Isaan people are Buddhist and are generally happy and friendly people. Many Isaan people are poor and the temptation to overcharge tourists is common as the perception is that 'falang' are wealthy. Compared to the average earnings in Isaan, tourists are wealthy and can probably afford to pay a few extra baht for a tuk tuk ride.

Respect
The inhabitants of Isaan tend to be direct communicators, i.e., you can expect them to tell you exactly what they think. Be mindful of that while you're here.
Go next
Phitsanulok - a gateway to Northern Thailand
Preah Vihear - magnificent Khmer temple in Cambodia, easy to reach from Isaan with no visa required
Vientiane - the once sleepy capital of Laos, becoming more and more discovered