The province is in the valley of the Mun River, a tributary of the Mekong. The Dângrêk mountain chain, which forms the border with Cambodia, is in the south of the province.
Khao Phra Wihan National Park covers an area of 130 km² of the Dângrêk mountains in the southeast of the province. Established on March 20, 1998, it is named after a ruined Khmer Empire temple Prasat Preah Vihear (anglicised in Thailand as Prasat Khao Phra Wihan), now in Cambodia, which had been the issue of boundary dispute. The temple faces north and was built to serve the Sisaket region. Earlier maps had all shown it as inside of Thailand. However, a boundary survey conducted by the French for the Franco-Siamese Treaty of 1907 deviated from the agreed-upon international divide by watershed in order to place the temple on the French (Cambodian) side.
The Thai government ignored the deviation and continued to regard the temple as being in Sisaket Province. In the mid 1950s, newly independent Cambodia protested the Thai "occupation" of what the French map showed as theirs. Since the French map was clearly incorrect, in 1962 the Thai government confidently agreed to submit the dispute to the International Court of Justice. To their dismay, the court voted 9 to 4 to confirm the border as shown in 1907 map and awarded the temple to Cambodia. Access to the temple is still principally from the Thai side, as the ruins are difficult to reach from the Cambodian plains at the bottom of a sheer cliff several hundred meters below. The Cambodian government has expressed interest in building a cable car to carry tourists to the site, though this has yet to happen, pending resolution of the ownership of other areas in the Cambodian–Thai border dispute.
The many Khmer ruins found in the province show the area must have been important to the Khmer empire at least by the 12th century, although it was apparently sparsely populated. According to local tradition, it was known as Sri Nakorn Lamduan (ศรีนครลำดวน.) It was later called Khukhan, after a town built in the late 15th century CE during the reign of King Boromaratcha III of Ayutthaya. Ethnic Laos began settling the northern portion of the province, and in 1786 the town Sisaket was formed, subject to Khukhan. In 1904, Sisaket was renamed Khukhan, while the original Khukhan was designated Huai Nua. Monthon Udon Thani was created in 1912, and assumed the administration of the most of region. In 1933 the monthon system was ended, and the province of Khukhan was administered directly from Bangkok. Five years later, the name of the town and province were restored to Sisaket, with the district containing Huai Nua being called Khukhan. (Thai: ศรี transcribed Sri in Sri Nakorn Lamduan and Si in Sisaket is the Thai honorific Si/Sri).
The Rasi Salai Dam built here in 1994 was unofficially decommissioned in July 2000, following devastation of local farming villages.
Sisaket is one of the provinces where there is a sizable northern Khmer population. In the 2000 census it was reported that 26.2% of the population are capable of speaking Khmer. This is down from the 1990 census when it was reported that 30.2% of the population were capable of speaking Khmer. The majority are Lao speaking people.
The provincial seal shows Prasat Hin Ban Samo, a Khmer temple about 1,000 years old, in the Prang Ku district.
The provincial flower and tree of the province is the White Cheesewood (Melodorum fruticosum). The six leaves of the flower symbolise the six original districts of the province: Khukhan, Kantharalak, Uthumphon Phisai, Kanthararom, Rasi Salai, and Khun Han.
The province is subdivided into 22 districts (amphoe). The districts are further subdivided into 206 subdistricts (tambon) and 2,411 villages (muban).
Sisaket province is famous for its ruins dating to the Khmer Empire. These include:
Tamnaksai ปราสาทตำหนักไทร (Tamchan ปราสาททามจาน) Khmer ruins – This is a single stupa of brick on a sandstone base. The stupa is rectangular. There is door on the east, while the other three sides have entrances with a door frame carved into the brickwork.
Bas relief - Carved on the red sandstone cliff, this depicts three gods in Khmer style. Khmer craftsmen probably practised here first before doing the actual carving for Preah Vihear sanctuary.
Sra Trao or Huay Trao - This stream runs through rock at the foot of Preah Vihear Mountain, before entering a subterranean tunnel strengthened by rock walls. It is assumed that the lowland was once used as a barai, a Khmer reservoir.
Phra That Ruang Rong (พระธาตุเรืองรอง) - The temple's architecture is a blending of art from four ethnic groups in the lower northeast: Lao, Suay, Khmer, and Yer. The Phra That Or stupa is 49 metres tall.
Sra Kampaeng Noi (ปราสาทสระกำแพงน้อย) - These Khmer ruins include a laterite stupa and chapel with a big pond at front, all within a laterite wall. In the 13th century, additions were made in the Bayon architectural style. It once contained a community hospital known as the Arokaya Sala.
Sra Kampaeng Yai (ปราสาทสระกำแพงใหญ่) Khmer ruins - This is the largest and most complete Khmer complex in the province. The site includes three stupas on the same north-south axis and facing east. It was originally a shrine dedicated to Shiva, but was converted to a Mahayana Buddhist temple in the 13th century.
Huay Tap Tan (ปราสาทห้วยทับทัน) or Ban Prasart (ปราสาทบ้านปราสาท) Khmer ruins - This consists of 3 brick stupas on laterite base aligned on a north-south axis. They stand inside laterite walls with arch gates. The carved lintels depicting the churning of the sea of milk lies in front of the south stupa.
Plang Ku (ปราสาทปรางค์กู่) Khmer ruins - The stupa of this Khmer ruin complex was built in gigantic size. In front of Plang Ku is a big pond which is home to ducks and geese, which gather from February onwards.
Ban Samor (ปราสาทบ้านสมอ) Khmer ruins - This small Khmer ruin is in Moo 2 Ban Tamchan, Tambon Samor. Built in the 13th century, its stupa houses a carved statue.
Taleng (ปราสาทตาเล็ง) Khmer ruins - This features a single stupa standing on a rectangular base. The stupa's base faces east. Only the front wall and some side walls remain.
Preah Vihear (ปราสาทเขาพระวิหาร) sanctuary - The famous cliff-top Khmer sanctuary is in a disputed area between Thailand and Cambodia. It was listed as an antique architectural site by the Royal Thai Fine Arts Department, with an announcement in the Royal Gazette on 11 October 1940. The ruins are claimed by Thailand to be on the Thai side of the natural watershed which, according to the agreed determination between France and Siam in 1907, would place them inside the borders of Thailand. However, on 15 July 1962, the International Court of Justice ruled that the Hindu sanctuary belongs to Cambodia, citing Thailand's acceptance of the map of the 1907 determination which clearly showed the temple to be on Cambodian soil. Access must still be made through Thailand, since it is difficult to reach from the Cambodian plains 100 meters below. An area of 4.6 square kilometers adjoining the temple is claimed by both countries and has been the scene of sporadic clashes between Thai and Cambodian border patrols.
Wat Maha Buddharam (วัดมหาพุทธาราม) - This Buddhist temple's vihara houses Luang Por To, the sacred icon of Sisaket. Dating back to the Khmer era over a thousand years ago, the statue was carved from stone.
Khao Phra Viharn National Park (อุทยานแห่งชาติเขาพระวิหาร) - The park features dry evergreen forest, mixed dipterocarp forest, and deciduous dipterocarp forest with tree species like Pterocarpus macrocarpus, Shorea siamensis, and Xylia xylocarpa var. kerrii. It is home to wildlife such as boars, deer, barking deer, rabbits, squirrels, gibbons, and civets. Phra Viharn National Park features interesting sights including:
Double Stupas - Two sandstone stupas, or "phra that", cube-shaped with round tops, are west of Mo E-Dang cliff. The stupas house items that indicate the prosperity of the Khmer period.
Don Tuan - Built during the 10-11th centuries, the Khmer ruins in Ban Phume Sarol are 300 metres from the Thai-Cambodian border. Legend has it that a lady known as Nang Nom Yai or Nieng Non dor (in Khmer), stopped to rest here on her way to visit a king.
Mo E-Dang - One of the best viewpoints in the northeast, the red rock cliff face is on Thai-Cambodian border.
Namtok and Tham Khun Sri - The three-tiered waterfall, above the cave, is west of Sra Trao close to the trail to Phreah Vihear. Khun Sri Cave is of gigantic proportions and was believed to have been the accommodation of Khun Sri, a nobleman who controlled rock cutting at Sra Trao at the time of the construction of Preah Vihear sanctuary.
Namtok Phu La-Ō (น้ำตกภูละออ) - In Phanom Dongrak Wildlife Sanctuary, Tambon Sao Thongchai, the small waterfall turns vibrant from September to February.
Somdet Sri Nagarin Park (สวนสมเด็จศรีนครินทร์) - With a landscape of rolling hills, the park is nourished by two streams, Huay Poon Yai and Huay Poon Noi that meet north of the park. The area is rich in "Lamduan" or Lamdman trees, making it a botanical excursion.
Fruit Orchard of Sisaket (เส้นทางเที่ยวชมสวนชิมผลไม้ศรีสะเกษ) - Some 5 km from Amphoe Kantaralak, on the right of Hwy 226 (Kantaralak-Pha Mor E-Dang) there is a 20 km (16 km) asphalt road cutting through villages. These villages are significant fruit producers of Sisaket. Their major products include rambutan, durian, longan, mangosteen, stink beans, and rubber.
Khun Ampai Panich Building (ตึกขุนอำไพพาณิชย์) - The beautiful building belongs to Sisaket nobleman Khun Ampai Panich (in Naga-siharat). It is well-renovated and preserved, and won gold medal for conserving urban architecture in 1987.
Wat Pa Maha Chedi Kaew (Wat Larn Kuad) (วัดป่ามหาเจดีย์แก้ว [วัดล้านขวด]) - The Buddhist temple is constructed of millions of colourful glass bottles donated by the people. Its architecture is interesting, particularly the pavilion called "Sala Thansmo Maha Jedikaeo", an ubosoth located mid-pond.
Namtok Samrong Kiat (Namtok Pisad) (น้ำตกสำโรงเกียรติ [น้ำตกปีศาจ]) - Originating in Kantung Mount in the Bantad Range, this medium-sized waterfall turns vibrant from September to February.
Namtok Huay Chan (Namtok Kantrom) (น้ำตกห้วยจันทร์ [น้ำตกกันทรอม]) - Originating on Phu Salao Mountain in the Bantad Range, the waterfall cascades beautifully before meeting the Mun River.
Sisa Asoka (ศีรษะอโศก) - is a model of communal self-sufficiency, showcasing people who live a Buddhism-centric lifestyle. Its success attracts numerous organisations to study its story.
Sisaket is famed for silk and cotton cloth woven in khit pattern, which is produced mainly in Amphoe Bung Boon and Uthumporn Pisai.
Salted eggs from Amphoe Prai Bung, red onions, garlic, and preserved garlic in honey are generally available. Sisaket is also famed for its tropical fruits. Fruit orchards in Amphoe Kantaralak bear fruit such as durian, rambutan, and mangosteen from May to July.
Dok Lamduan Festivals (งานเทศกาลดอกลำดวน) - Held annually between March 15–17 at Somdet Sri Nagarin Park when lamdman trees in the park are in full bloom, The fair consists of cultural performances by four local ethnic groups: Khmer, Suay, Lao, and Yer. Visitors can view handicrafts, local products, and watch reenactments of Sisaket's history.
Sisaket's Rambutan and Durian Fair (งานเทศกาลเงาะทุเรียนศรีสะเกษ) - The fair is held every June on the field before Amphoe Kantaralak or Amphoe Khun Harn. Fairgoers can marvel at the fruits of Sisaket, rambutan, durian, lanson, mangosteen, stink beans and enjoy flower floats, documentary exhibitions, and a fruit tasting caravan.
Half- and Quarter-Marathon to Mor E-Dang (การแข่งขันวิ่งฮาล์ฟและควอเตอร์มาราธอนสู่ผามออีแดง) - Held annually on the third Sunday of December, the half- and quarter-marathon proceeds from Ban Phume Sarol to Mor E-Dang Cliff, on the way to Preah Vihear.