In most cases. You should Thourougly search and Research the area first. 

If it is Marked with a "Plaque" Stating that it is a 'Historic Site' then Don't.

If it is Marked as a 'Archeological Site' then Don't.

If it is Marked as 'Private Property' and "No Trespassing" then Ask the Owners. (Just because there are Signs Posted does not mean the person actually owns the land. They may have just placed them up there as a 'Land Grab'. Check with the Township or County if that's the case, then if a 'Land-Grab' is going on, Report it.)

State Game Area: Is an Area for 'Hunting' Game. It is Also used for Hiking and other Recreations. There Typically are No Historic, Religious, or Native American Value to the Area. 'Metal-Detecting' has No Restrictions there.

State Park: A Place where People Generally go for Fun and Relaxation. Yes, There are Several Rules and Guidelines in these Places. Some Parks have no issue with 'Treasure Hunters', and some have Limited areas where one can use a 'Metal-Detector', and some Parks the Use of 'Metal-Detectors' is Illegal.

I Advise that you Perform a Through Legal Search of each 'State Park' that you wish to Explore.

NO. You will be Arrested and Fined.

NO. You will be Arrested and Fined.

Generally; NO. 

But; It does not hurt to ask. Offer a Share of the Finds or give an Monetary Value for the timeframe that you want to search.

Record every Agreement.

First; Did you check to see the Laws of the 'Park', 'Game Area', 'Historic', or 'Private Property' of the Area?

Second; Did you Check for 'Plaques' or 'Signs' Stating the 'Significance of the area'?

DO AS MUCH RESEARCH TO THE AREA AS YOU CAN BEFORE VENTURING OUT.

If the Laws don't 'Clearly State' that you cannot be on the Property, or using a 'Metal-Detector' at the area you are searching, there are Not any "No Trespassing" Signs that cannot be Challenged, as long as you are doing your 'Hobby' Respectfully, No-One can tell you otherwise. 

If an 'Archeologist' and an 'Officer' approaches, Respect their Authority, but make Clear; "I am in No Violation of Any Laws pertaining to this area for Search with this Device, the Metal-Detector, and your aggression to My Person is taken as 'Harrassment'. If I find anything Significant to your Fields of Profession, or any other Profession, I will Alert that Authority." (Make sure you get names and Any Badge Numbers). "I have performed the Research for this area and am in No Violation of any of them. May I have your Business Cards or your Fields Identification Numbers?" (Get whatever information that you can). 

If an Civilian Approaches (With or Without an Officer) make clear; "I am in no Violations of Any Laws. I am here persuing a Hobby and wish to be Left Alone."

If the Person Starts Harassing you; "Do you have Legal Ownership to this Property? Can I go to the County Seat, or the Land Commission and Find that you have Purchased this Land?" (Do NOT Accept Their Word.)

If the Person Threatens to call the Authorities; "I will Contact the State Police Office for you." (Because they will call the Local Authority who will be on their side.)

If the Person has actual Claim to the Land; Either Leave, or Offer them a Share of the Find.

I have Read Witness Statements on Sites Dedicated to the Search with 'Metal-Detectors' of 'Archeologists' Bringing an 'Officer' with them to Deter People from Searching areas and Finding Artifacts. Even though they were in the 'Wrong' they had the 'Officer' as a way to Manipulate the situation to their Favor even though they knew they were in the wrong. Make sure that where you are Searching is NOT an 'Site of Cultural Importance' to the Indeginous People or has been Marked with a 'Plaque' or 'Archiological Dig' Paper.

Depends on the Area and amount of work you wish to Achieve, and do you want to Split the Finds.

New Places/Sites, I would for the Company.

As for the Finds; you can either pool everything together and split the sum of the money that you get from them with the exception of being able to personally keep a piece or two. or, You just Keep what you find and do it as you wish.

I would Record where I had found everything and it's Oreintation to North, then Call the Appropiate Authorities, or Find someone who knows who to contact, and then turn over all of the Artifacts (After I take Pictures).

I am going to Determine that by 'Averages' in the Samples. I realize that in some places it may be as far as 3 to 6 feet down for 100 years past, and in others it may be 3 to 6 inches to reach 100 years past. So, this Team will have to make a set of Drawings and take several Samples recording Soil Types and their Stratifications and where Artifacts of 100 years ago are. There will be a lot of Pictures and Drawings Coming in concearns of this issue. If the Issue ever has to come to Court I want some Solid Information to Rely on. Something that Scientists ('Archeologist') cannot Argue with. 

Keep visiting this Site for Updates Concearning Soil Stratifications and Era Marks.

It is Extreemly Time Consuming and Complicated. What I would Suggest for you to do: Stay with the State Parks and Check everywhere everyone else had done for the last 50 or so years.

No? NO!? Not Good Enough?

Well then...

Start Researching the Area with whatever tool that you can think of. Use Satellite Images, Search your Local Offices for maps of Decades past, Compare what is to what was. Learn the Laws of the Area and how they pertain to the Hobby of 'Metal-Detecting'. 

Yes, It's 'Time-Consuming' as I originally Stated, but if you want to persue this, have an Understanding of the Area before going out, and select several areas so if one does not pan out, you have a back-up, or two.