This is a very incomplete, yet formulating list of Fossil Hunting areas open to the public across the United States. Please leave a comment if you would like to share any sites in your area.
The goal is to include links and information about each, to help in panning trips, and sharing recent field reports.
I live nearby and frequent the Mazon Creek formation in Illinois, I am a born and raised midwesterner, so forgive the current bias. I do hope to visit all of these all someday.
California
Shark Tooth Hill
Location: Bakersfield, California
Types of fossils: Shark teeth, marine mammal bones
Common finds: Megalodon, Mako and other shark teeth
Bakersfield, Shark Tooth Hill
Bakersfield, Ernst Ranch, this ranch is very close, but separate from what is known as “Shark Tooth Hill,” there is a $70 fee but I have read it is worth it, @Nicholas_celozzi and @jamesprola on instagram have some good photos from the area.
Colorado
White River Formation
Illinois
Mazon Creek
Public Friendliness: 100%
Difficulty Level: Very Hard
Location: Braidwood/Morris,IL
Types of fossils: Pennsylvanian age Carboniferous concretions, 300-350 million years old.
Common Finds: Jellyfish, an otherwise rarely preserved animal, are quite common here, among ferns, calamites, other plant material, worms, and the occasional insect.
How to collect here: Just an hour’s drive from downtown Chicago, this world-class fossil site has 100+ acres of land from a former strip mine open for public fossil hunting to anyone from March 1-Sept 30th. The site here is called the Mazonia Braidwood Fish and Wildlife area, a permit is required to fill out and carry with you. The terrain can be quite difficult, and the area allows for surface collecting only, so you will be hiking through the woods, looking for round and brown concretions in eroded hills and ridges with exposed areas.
Resources and links:
- American Fossil Hunt’s Field Guide will save you hours of hiking by mapping out the best spots to make the most of your trip: Fossil Collecting Mazon Creek: The Ultimate Field Guide eBook
- Official Illinois Department of Natural Resources web page: https://www.dnr.illinois.gov/Parks/Pages/Mazonia-Braidwood.aspx
- Fossil Collecting Permit: americanfossilhunt.com/mazon-creek-fossil-hunting-permit-pit-11-pdf
- Field Reports can be found on my personal blog: http://chicagorants.com/tag/mazon-creek-fossil-collecting/
- The Fossil Forum also has a wealth of other first-person perspective collecting, simply search “Mazon Creek”: http://www.thefossilforum.com/
Maryland
Calvert Cliffs
Instagram Photo by Ross Sholota
Public Friendliness: 100%
Difficulty Level: Easy
Location: Lusby, MD
Types of fossils: Miocene Shark Teeth, Gastropods
Common finds: Mako Shark and Megalodon Teeth
How to Collect Here: There are 5 locations in this area for public 
collecting, those that require a fee are noted here. They are all within an hours drive on the same coast. Sources online recommend Brownies Beach/Chesapeake Beach the most, and during the summer there is a fee based on residency and age ranging from $5-$16. Breezy Point is another beach with a $4-$6 fee where a lot of shark teeth can be found. There is also a campground right near the beach that has good reviews. Matoaka Cabins has a nice area of beachfront available to their visitors, but also offer a fee for a day trip for those not staying in the cabins. Flag Pond is a site listed for collecting, but I’ve read mixed reviews of the quality of fossils hunting area, as much of it is off limits to protect the habitat of an endangered beetle. Calvert Cliffs Sate Park is known for some good finds, but the collecting area is very small here, and frequently searched.
Resources and links:
- Full brochure on collecting this area: http://www.choosecalvert.com/DocumentCenter/View/3
- Official Maryland Department of Natural Resources site: dnr.maryland.gov/publiclands/Pages/southern/calvertcliffs.aspx
- Fossil Guy’s web page and guide: http://www.fossilguy.com/sites/calvert/
- Maryland Geological Survey Fossil Collecting: www.mgs.md.gov/geology/fossils/fossil_collecting.html
- A nice field report from 2015 on this blog: http://foragingforflavor.com/brownie-beach-for-shark-teeth/
- Matoaka Cabins website: http://www.matoakabeachcabins.com/
Nevada
Humboldt Mountains
Fossil Hill
http://www.collectingfossils.org/fossils-america/nv/nevadafossilsites.htm
New Jersey
New York
Penn Dixie
North Dakota
Hell Creek
Ohio
Fossil Park, Sylvania, Ohio
Florida
Peace River
Public Friendliness: 100%
Difficulty Level: Medium
Location: The Peace River cuts through many cities, but a common starting point is Arcadia, FL
Types of fossils: Miocene to Pliocene Shark Teeth, Mammal Bones
Common finds: Lemon, Tiger, Hemi, Megalodon Shark Teeth, Alligator Teeth, Dugong Bones
How to Collect Here: I mark the Peace River at Medium difficulty, because you will need tools, a sifter, a large garden shovel, and a “probe.” You will also need to do some walking, wading, and potentially light canoeing or kayaking.
After using the probe to find a gravel-laden spot of the river bed, you scoop shovelfuls of the mixture onto a fine sifting screen (available at some gift shops around the area). Shaking out the sand and fine gravel will leave you with many dime-sized pebbles that you sort through for easy-to-spot shark teeth and other fossils. There are also many guides in the area who, for a reasonable fee, will take you out for a great day on the water. My experience and trip report with Fossil Funatics is below:
http://americanfossilhunt.com/2017/01/21/shark-tooth-hunting-peace-river-2017-trip-report/
Water level is an important factor for collecting here. It varies throughout the year, and is best when levels are at least 12” below normal, usually the winter or spring. You can see the current water level in this link.
Gainesville
Venice Beach
Texas
Jacksboro
Mineral Wells Fossil Park
Wilson Clay Pit
Whiskey Bridge near Bryan, TX
North Sulphur River
Utah
Antelope Springs
http://www.u-digfossils.com/location.html
Wyoming
Green River Formation
