From Seattle, you can ride Sounder Rail right to the Sumner Station in the heart of downtown Sumner.  The ride is approximately 35 minutes long.  (Usually available only on weekdays.)

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Also, from Eugene, Portland or southern Washington cities, you can ride Amtrak to the Tacoma station and transfer to a Sound transit train to Sumner.  (Usually available only on weekdays.)

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PLANE

Sumner is approximately 25 minutes from Seatac Airport. 

Seatac Website

You can either rent a shuttle, use the Holiday Inn Express Sumner shuttle (if staying at the hotel) or rent a car.

If driving yourself, follow these directions:

Take Hwy 518 East.

Hwy 518 becomes I-405 North. Continue.

Take the Hwy 167 exit, toward RENTON/AUBURN.

Merge onto Hwy 167 South to KENT/AUBURN.

Merge onto Hwy 410 East to SUMNER/YAKIMA.

Take the E. MAIN/TRAFFIC AVE. exit.

Turn LEFT onto TRAFFIC AVE.