There’s so much to learn about Islip, but there’s no need to feel overwhelmed. Before you drive off in your rental car, let’s get started with the basic facts.This town sits 6 miles to the west of West Sayville, and 236 miles northeast of Washington, the nation’s capital.If you’re traveling with the youngsters and they’re getting bored of road trip bingo, why not quiz them to see if they know what the population of this part of Suffolk County is? (If you’re not too sure yourself, it’s 18,700!)