Zip Code 77365 Cities. 77365 is located in the state of Texas in the Houston metro area. Zip code 77365 is primarily located in Montgomery County. Portions of 77365 are also located in Harris County. The official postal service name used for 77365 is PORTER, Texas. Portions of the 77365 zip code are contained within or border the city limits of Houston, TX, Porter Heights, TX, Spring, TX, and Humble, TX. Zip code 77365 is part of area code 281, area code 832 and area code 713.