Warren Dunes is about 90 minutes from Chicago by car, which is why it draws so many day-trippers from the city. Take I-94 east into Michigan and exit at Sawyer (Exit 12), then follow Red Arrow Highway south to the park entrance on Floral Road. The drive is straightforward and the last stretch runs through farmland and small towns before the dunes come into view. There is no practical public transit option — a car is essentially required.
The nearest major airports are Chicago O'Hare (ORD) and Chicago Midway (MDW), both roughly two hours from the park by car depending on traffic. If you are flying in specifically for the park, Midway is marginally closer and tends to have less airport congestion. South Bend Regional Airport (SBN) in Indiana is about 45 minutes away and serves several carriers if you prefer a smaller airport. All visitors pay a Michigan State Park entry fee of $13 per vehicle; an annual Recreation Passport is available for $17 and covers all Michigan state parks for the calendar year, which makes it worthwhile if you plan to visit more than once.