An acknowledgment is a formal declaration by a person or other legally recognized entity, such as a corporation, that execution of a document or instrument is his/her free act and deed.  Execution of an instrument means that it has been drafted and signed.  When a person acknowledges the execution of an instrument, he/she is stating that his/her signing of it is his/her free act or deed.  The acknowledgment is made before a person, such as a notary public, authorized by law to take an acknowledgment.  Please see specific state for details and/or differences.

Black’s Law Dictionary, Fifth Edition.

ALABAMA | ALASKA | ARIZONA | ARKANSAS | CALIFORNIA | COLORADO | CONNECTICUT | DELAWARE | FLORIDA 
 GEORGIA | HAWAII | IDAHO | ILLINOIS | INDIANA | IOWA | KANSAS | KENTUCKY | LOUISIANA | MAINE | MARYLAND 
 MASSACHUSETTS | MICHIGAN | MINNESOTA | MISSISSIPPI | MISSOURI | MONTANA | NEBRASKA | NEVADA 
 NEW HAMPSHIRE | NEW JERSEY | NEW MEXICO | NEW YORK | NORTH CAROLINA | NORTH DAKOTA | OHIO 
 OKLAHOMA | OREGON | PENNSYLVANIA | RHODE ISLAND | SOUTH CAROLINA | SOUTH DAKOTA | TENNESSEE 
 TEXAS | UTAH | VERMONT | VIRGINIA | WASHINGTON | WEST VIRGINIA | WISCONSIN | WYOMING

ALABAMA
In Alabama, an instrument may be acknowledged to be recorded.  An acknowledgment makes an instrument self-proving in court.  Alabama Code §35-4-58.

ALASKA
In Alaska, an instrument must be acknowledged to be recorded.  An acknowledgment makes an instrument self-proving in court.  Alaska Code §40.17.090.

ARIZONA
In Arizona, an instrument must be acknowledged to be recorded.  An acknowledgment makes an instrument self-proving in court.  Arizona Code §12-2261; 33-411.

ARKANSAS
In Arkansas, an instrument must be acknowledged to be recorded.  An acknowledgment makes an instrument self-proving in court.  Arkansas Code §16-47-101, 110;  18-12-201, 209.

CALIFORNIA
In California, an instrument must be acknowledged to be recorded.  An acknowledgment of an instrument constitutes prima facie evidence of the facts recited in the instrument.  Prima facie means that a fact is presumed to be true unless evidence to the contrary is shown.  California Gov’t. C §27293;  Evide. C. 1451.

COLORADO
In Colorado, an instrument may be, but need not be, acknowledged to be recorded.  An acknowledgment of an instrument is prima facie evidence of proper execution of it.  Colorado Code §38-35-101.

CONNECTICUT
In Connecticut, an instrument must be acknowledged to be recorded.  Connecticut Code §47-5.

DELAWARE
In Delaware, an instrument must be acknowledged to be recorded.  Delaware Code §29-4321 onward.

FLORIDA
In Florida, an instrument must be acknowledged to be recorded.  Florida Code §695.03.

GEORGIA
In Georgia, an instrument must be acknowledged to be recorded.  An acknowledgment does not make an instrument self-proving in court.  Georgia Code §44-2-14, 15.

HAWAII
In Hawaii, an instrument must be acknowledged to be recorded.  An acknowledgment makes an instrument self-proving in court.  Hawaii Code §502-41, 47, 50, 81.

IDAHO
In Idaho, an instrument must be acknowledged to be recorded.  Idaho Code §55-805.

ILLINOIS
In Illinois, an instrument does not need to be acknowledged to be recorded.  An acknowledgment does make an instrument self-proving in court.  Illinois Code §765-5/35.

INDIANA
In Indiana, an instrument must be acknowledged to be recorded.  Indiana Code §32-1-2-18.

IOWA
In Iowa, an instrument must be acknowledged to be recorded.  Iowa Code §558.42.

KANSAS
In Kansas, an instrument must be acknowledged to be recorded.  An acknowledgment makes an instrument self-proving in court.  Kansas Code §58-2221, 2229.

KENTUCKY
In Kentucky, an instrument must to be acknowledged to be recorded.  Kentucky Code §382.130.

LOUISIANA
In Louisiana, an instrument must be acknowledged to be recorded.  An acknowledgment makes an instrument self-proving in court.  Louisiana CC §2242, 2253.

MAINE
In Maine, an instrument must be acknowledged to be recorded.  Maine T.4, §1011-1019.

MARYLAND
In Maryland, an instrument must be acknowledged to be recorded.  An acknowledgment alone does not make an instrument self-proving in court.  The instrument also must be certified.  Maryland Real Prop. Art. §4-101;  Courts Art. §10-204.

MASSACHUSETTS
In Massachusetts, an instrument must be acknowledged to be recorded.  Massachusetts C. 183, §29-30.

MICHIGAN
In Michigan, an instrument must be acknowledged to be recorded.  An acknowledgment creates a presumption that the acknowledged instrument is valid and genuine.  Michigan CLA §565.201-.203;  600.2131.

MINNESOTA
In Minnesota, an instrument must be acknowledged to be recorded.  An acknowledgment makes an instrument self-proving in court.  Minnesota Code §507.24;  600.14.

MISSISSIPPI
In Mississippi, an instrument must be acknowledged to be recorded.  Mississippi Code §89-3-1.

MISSOURI
In Missouri, an instrument must be acknowledged to be recorded.  Missouri Code §442.010 onward; 59.330.

MONTANA
In Montana, an instrument must be acknowledged to be recorded.  Montana Code §70-21-203, 205, 207.

NEBRASKA
In Nebraska, an instrument must be acknowledged to be recorded.  An acknowledgment makes an instrument self-proving in court.  Nebraska Code §76-233-35.

NEVADA
In Nevada, an instrument must be acknowledged to be recorded.  Nevada Code §111.310, .312.

NEW HAMPSHIRE
In New Hampshire, an instrument must be acknowledged to be recorded.  New Hampshire C.477, §3.

NEW JERSEY
In New Jersey, an instrument must be acknowledged to be recorded.  An acknowledgment makes an instrument self-proving in court.  New Jersey Code §46-14-2.1.

NEW MEXICO
In New Mexico, an instrument must be acknowledged to be recorded.  New Mexico Common Law §14-14-1 onward.

NEW YORK
In New York, an instrument must be acknowledged to be recorded.  An acknowledgment of an instrument is prima facie evidence that it was executed by the person whose signature appears on it.  New York C.P.L.R. Rule 4538; R.P.L. §291.

NORTH CAROLINA
In North Carolina, an instrument must be acknowledged to be recorded.  North Carolina §47-14.

NORTH DAKOTA
In North Dakota, an instrument must be acknowledged to be recorded.  North Dakota Code §47-19-03.

OHIO
In Ohio, an instrument must be acknowledged to be recorded.  An acknowledgment makes an instrument self-proving in court.  Ohio Code §317.112; 5301.01.

OKLAHOMA
In Oklahoma, an instrument must be acknowledged to be recorded.  An acknowledgment makes an instrument self-proving in court.  Oklahoma Code §16-26, 27.

OREGON
In Oregon, an instrument must be acknowledged to be recorded.  Oregon Code §93.010, .530, .635; 86.100.

PENNSYLVANIA
In Pennsylvania, an instrument must be acknowledged to be recorded.  An acknowledgment is prima facie evidence that an instrument was property executed.   Pennsylvania Code §21-42 through 46.

RHODE ISLAND
In Rhode Island, an instrument must be acknowledged to be recorded.  An acknowledgment makes an instrument self-proving in court.  Rhode Island Code §34-12-6.

SOUTH CAROLINA
In South Carolina, an instrument must be acknowledged to be recorded.  South Carolina Code §30-5-30; 26-3-20 through 90.

SOUTH DAKOTA
In South Dakota, an instrument must be acknowledged to be recorded. South Dakota Code §43-28-2, 3, 8, 10.

TENNESSEE
In Tennessee, an instrument must be acknowledged to be recorded.  An acknowledgment makes an instrument self-proving in court.  Tennessee Code §66-22-104 onward.

TEXAS
In Texas, an instrument must be acknowledged to be recorded.  Texas Prop. Code §12.001.

UTAH
In Utah, an instrument must be acknowledged to be recorded.  An acknowledgment is prima facie evidence that the instrument was executed by the person(s) whose signature appears on it.  Utah Code §57-3-1.

VERMONT
In Vermont, an instrument must be acknowledged to be recorded.  Vermont Code §27-341.

VIRGINIA
In Virginia, an instrument must be acknowledged to be recorded.  Virginia Code §55-106, 113.

WASHINGTON
In Washington, an instrument must be acknowledged to be recorded.  Washington Code §65.04.030; 65.08.060-.070.

WEST VIRGINIA
In West Virginia, an instrument must be acknowledged to be recorded.  West Virginia Code §39-1-2.

WISCONSIN
In Wisconsin, an instrument must be acknowledged to be recorded.  Wisconsin Code §706.06, 706.07.

WYOMING
In Wyoming, an instrument must be acknowledged to be recorded.  An acknowledgment makes an instrument self-proving in court.  Wyoming Code §34-1-118, 123.