 Washington State History. Reading a map. A map shows land and water. A map usually has a key. The key uses symbols to show places on the map. This is a map of Washington State. You can see the key on the left. There are cities, highways, mountains, rivers, and an ocean. This part of the key shows the sizes of the population of cities with bigger or smaller letters. This part of the key shows symbols for highways and other forms of transportation. This part of the key shows symbols for streams, rivers, lakes, mountains, and the ocean. This part of the key shows distance in miles. This is a compass rose. It shows the directions north, south, east, and west on the map. Here you can see many cities in Washington State and their sizes. Here you can see three mountain ranges in Washington State. The Olympic mountains are by the Pacific Ocean. The cascades are in the middle. The Wenatchee Mountains are east of the cascades and are smaller. The Columbia River is a large river between Washington and Oregon. Interstate 5, or I-5, is an important highway in Washington State. Last, the Pacific Ocean is to the west of Washington State.