Annandale Community Park features a tennis court, playground, basketball court, baseball field and walking trail. There is also the Hidden Oaks Nature Center nearby. Walk-on usage of sites and facilities is free, first come, first served. If you would like make a reservation, go to the Fairfax county website. Click on 'Find a Park' and make your selection. Here you will also find a calendar and information on reservation instructions, cost and times.