There is NO cost to walk the trail. There is a fee to park. The most recent information on the nps.gov site says it is $10 per vehicle; prices may vary depending on vehicle size. Lower prices apply to senior citizens.
Esther is correct. The entire national memorial is free to visit yet a parking is charged; due to the layout there is no way to avoid parking unless one came in on foot from multiple miles away.
Nine years ago my family of four was charged $11 for our mini van. Last June the 54 seat motor coach i drove 37 people In was charged $50.
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