Location of Sentinel, Oklahoma
Sentinel is located at  (35.156659, -99.173829).
According to the United States Census Bureau, the town has a total area of 0.6 square miles (1.6 km2), all land.
Sentinel is located in western Oklahoma's Washita County at the intersection of Highway 44 and Highway 55.
The Sentinel School District has a large geographic area consisting of over 200 square miles (520 km2). The present school plant was constructed in the 1960s. Sentinel is a class 'A' school. Students from the communities of Sentinel, Port, Rocky, and Carter attend Sentinel Public Schools.
Sentinel public School is a member of the Western Technology Center District. WTC provides the opportunity for adults and high school students to get occupationally-specific training. As a member of the WTC district, high school juniors and seniors living in the Sentinel School District have the opportunity to attend classes at the WTC campus in Burns Flat. High school students who are residents of the WTC District can enroll in WTC full-time training on a tuition-free basis. Adult students are allowed to attend classes on a tuition basis. Tuition for adult students is $2.00 per training hour. Adult students can apply for financial assistance to attend WTC.