For Mansfield Dam Park in Austin, a day visit costs $5 per person. Seniors 62+ pay $3 per person , children 12 and under are free , and disabled veterans with 50%+ disability are free.

A couple of practical details:

  • They accept cash only at the entrance booth.
  • Trailer parking costs $7 per trailer per day.
  • The park is open sunrise to civil twilight.

If you meant a different “Mann Dam,” the price could be different, since the name is a bit ambiguous.