Farms and Fields
If you own a farm anywhere in the U.S., you may chance upon arrowheads or other artifacts after plowing fields. You may also find them by chance, when walking through old cotton or wheat fields. Arrowheads are periodically found on the surface of farms and fields, but digging may turn them up also, especially in areas once populated by tribes. A certain responsibility comes with any arrowhead find, so use your head. If you are visiting a friend's farm, or if you have received permission to look for arrowheads on any rural properties in which the Iroquois or Comanche once lived, you may not be able to keep or even pick up an arrowhead you discover.
Rivers and Dry Beds
A big rainfall occurs in Idaho, Oregon, Mississippi or Alabama. The soil is washed away, leaving not only debris, roots and rocks revealed, but possibly an arrowhead has been uncovered. If you scout areas near rivers and streams where tribes lived thousands of years ago, you may find arrowheads lodged in the mud or lying on ground surfaces near a bend in the river. Dried up old river beds in the Midwest sometimes yield arrowheads and you may spot one when walking the area. Some people go to such areas with a few basic tools and dig, illegally or with permits. You will have to find out which areas allow people to sift sand and soil or dig for such prizes as arrowheads.
In the Desert
Though some dry river beds lie in desert regions, the desert also yields arrowheads at old cooking and camp sites. You may be on a hike in Texas, Wyoming, New Mexico or Arizona and stumble upon a fine arrowhead specimen lying right beside a trail. Maybe you set up your own camp in a desert campground or after doing a spirit quest, and the lowering sun glints off an object near where you dug in a tent peg. On closer inspection, you find arrowhead chips. Depending on who owns the land, you could continue to search the vicinity in hopes of finding other artifacts.
Elsewhere
Caves that may have once housed tribal peoples would be a place to search for arrowheads. Many of the known caves have already been discovered, but smaller ones still exist and spelunkers could find arrowheads either by accident or intention. Sometimes people find arrowheads at seaside areas by chance. These may have washed up or been rinsed from nearby hillsides and bluffs. Deltas or sites left after excavation by archaeologists could also have whole arrowheads or chips lying around. Remember, it's your responsibility to know the laws regarding these finds.