Houston Area, Texas, USA November 1998 At least ten major highways converge near downtown Houston (concentrated, bright spot near center of the image), the fourth most populated city in the United States. These highways include Interstate Highways 10 and 45, as well as several other state highways. The gridded, north-south and east-west street pattern within the urban area and the outer beltway (Sam Houston Tollway) can be traced around the outskirts of the growing metropolitan area. The uniform looking dark green areas north and east of the city are mainly undeveloped, heavily wooded, floodplain of the San Jacinto and Trinity Rivers. Houston’s international ocean traffic route can be traced through Galveston Bay (by the pattern of darker sediments around the dredged channel) to port facilities in the Houston Ship Channel (dark line with white edges that extends east from near downtown Houston). The opaque, oval-shaped feature on the east edge of the image is Lake Anahuac