Marsing water tower, photographed from Knob Lane and Patton Street in Marsing, Idaho. – Tamanoeconomico, CC BY-SA 4.0 – Wikimedia Commons Marsing is located in Owyhee County. About 1,229 people live here (as of 2020). Between 2010 and 2020, the population grew from 1,031 to 1,229. The region is at 700 meters above sea level. The area covers about 1.8 square kilometers. There are about 96 streets in Marsing. The postal codes are 83639. The dialing code is 208. Marsing is city in Owyhee County, Idaho, United States. Among other things, Marsing has cafés and schools.