Welcome to T-Net! Where I'm at in AZ the local parks and any of the unfenced athletic complexes are fair game. City ordinance allows it. Inside the fences can be accessed if permission is granted. The main consideration is digging properly and leaving no trace you were there. There are also a few school yards accessible (after school hours of course) but they leave gates open. Most here don't. Generally speaking, any place else requires permission, certainly private property. Fair grounds are great too but permission is required even if the gates are left open. I asked and was old to go ahead. I hit the grounds occasionally and always after the fair is over. Any place people gather or once gathered is worth looking into for permission. Also, if you see a street or sidewalk being torn up, especially in the older section of town, ask the workers on site if you can detect. I've usually been told to go right ahead as long as I stayed clear of any equipment. It's different everywhere. Just some ideas for you based on what I have available in my area. If I'm not sure I just move on.