High Island is an unincorporated community located in the Bolivar Peninsula census-designated place, Galveston County, Texas, United States. The community is located in the extreme eastern part of the county on Bolivar Peninsula, less than one mile from Chambers County and less than two miles from Jefferson County. As of 2000, 500 people resideā¦High Island is an unincorporated community located in the Bolivar Peninsula census-designated place, Galveston County, Texas, United States. The community is located in the extreme eastern part of the county on Bolivar Peninsula, less than one mile from Chambers County and less than two miles from Jefferson County. As of 2000, 500 people resided in High Island. The 2010 census did not record a population for High Island.