Most of the nation's national parks are free to enter.

But visiting some of the ones that do charge a fee could soon cost even more.

The National Park Service has proposed a plan to more than double the peak-season entrance fees at 17 of the country's busiest national parks, including Yosemite.

Under the plan, visitors would be charged $70 per vehicle during the peak summer season, up from the current $25 or $30 fee charged per vehicle no matter the season.

Per-person entry fees would rise from the current $10 to $15, up to $30 during peak season.

The National Park Service says the fee increases are necessary in order to address its maintenance backlog.

Public comments are being accepted now through November 23rd on the National Park Service's Planning, Environment and Public Comment website.