Sinclair refinery, Wyoming – Charles Willgren from Fort Collins, Colorado, United States, CC BY 2.0 – Wikimedia Commons Sinclair is located in Carbon County. About 374 people live here (as of 2020). Between 2010 and 2020, the population declined from 433 to 374. The region is at 2008 meters above sea level. The area covers about 6.3 square kilometers. There are about 45 streets in Sinclair. The region was founded in 1868. The postal codes are 82334. The dialing code is 307. Sinclair is town in Carbon County, Wyoming, United States. More information at www.sinclairwyoming.com.