What is a mortgage?

What is a mortgage?  
The mortgage is a list of covenants between you and the lender.  It says that as long as you abide by those covenants, the lender will leave you alone.  So, what are you agreeing to?
1.That your house is being used as collateral on the loan. So if you default on the loan, the lender will repossess your house and sell it.  With the sales proceeds they will pay off your loan.  If there is not enough sales proceeds to pay off your loan, then the lender will file a default judgment lien agains you which will prevent you form buying another home until it is paid off or released.  Most of a mortgage’s language is regarding this issue.
2. That you’ll keep the home in a general state of good repair, that you’ll keep the property insured, and that you’ll make your payments on time.  If you don’t make your payments on time, the loan can go into default.  Default is covered above.
3. It also says things like you cannot store any hazardous materials on the property.
These covenants are there so that in the unlikely event that the lender has to foreclose upon you, that a) they can do so, and b) the house is still in marketable condition.

A mortgage is a lien  A lien is a right to stand in line when a property sells, to get paid back the lien amount, plus interest/penalties.  Liens stack up in chronological order.  The first lien to be recorded at the clerk’s office is in “first position”. 2nd is in 2nd position, and so on.  Mortgage companies require their mortgage to you to be in first position, when you buy a house.
The mortgage must be recored at the county clerk’s office, in the county in which the property is located.
Yes, a mortgage is simply a lien held by a lender.  It essentially states, that if you pay you stay, and if you don’t, you won’t = meaning, if you default on your loan, you’ll be foreclosed upon and your home will be repossessed by the bank.  The bank will then sell the house and pay off/down your loan with the sales proceeds.  If there is not enough sales proceeds to pay off your loan (a “shortfall”), then the lender will file a default-judgment-lien against you, and you will not be able to buy another house without first paying off that shortfall, plus legal fees, interest and penalties.  You may be able to negotiate some settlement that is less than the full amount owed, in exchange for release of this default judgment lien – you may even get the lender to foreclose on you withOUT a default judgment for any shortage.
Attaches – Whenever a lien is recorded at the county clerk’s office, against a person, it automatically attaches to all pieces of real estate that person owns in that county.  The same lien may be recorded in multiple counties, in order to have it attach to all real estate the person owns in those counties – especially when a property is known to span county lines.3. Types – There are all types of liens: Mortgages, judgment liens, state/fed/local tax liens, unpaid child support liens, HOA liens, etc.
Expiration – Different liens are valid for different lengths.  Some do not have expiration dates. Call your local county clerk’s office.
Releases – Once a mortgage is satisfied (paid in full), then a release must be filed at the county clerk’s office by the lender, within 30 days or there will be penalties to the lender.  These penalties increase over time.