United States coinage was first minted by the new republic in 1792. New coins have been produced every year since then and they make up a valuable aspect of the United States currency system. Today circulating coins exist in denominations: $0.01, $0.05, $0.10, $0.25, $0.50, and $1.00. Also minted are bullion and commemorative coins. All of these are produced by the United States Mint. The coins are then sold to Federal Reserve Banks which in turn are responsible for putting coins into circulation and withdrawing them as demanded by the country's economy.

Current coinage

Today four mints operate in the United States producing billions of coins each year. The main mint is the Philadelphia Mint, which produces circulating coinage, mint sets and some commemorative coins. The Denver Mint also produces circulating coinage, mint sets and commemoratives. The San Francisco Mint produces regular and silver proof coinage, and produced circulating coinage until the 1970s. The West Point Mint produces bullion coinage (including proofs). Philadelphia and Denver produce the dies used at all of the mints. The proof and mint sets are manufactured each year and contain examples of all of the year's circulating coins. These and the other non-circulating coins can be purchased directly from the US Mint.

The producing mint of each coin may be easily identified, as most coins bear a mint mark. The identifying letter of the mint can be found on the front side of most coins, and is often placed near the year. Unmarked coins are issued by the Philadelphia mint. Among marked coins, Philadelphia coins bear a letter P, Denver coins bear a letter D, San Francisco coins bear a letter S, and West Point coins bear a letter W. S and W coins are rarely, if ever, found in general circulation, although S coins bearing dates prior to the mid-1970s are in circulation. The CC mark was used for a short time in the mid-nineteenth century by a temporary mint in Carson City, Nevada, but all such coins are now in the hands of collectors and museums.

Coins in circulation

Image		Value	Specifications				Description			Debut	Usage	Common Reference
Obverse	Reverse		Diameter	Thickness	Mass	Composition	Edge	Obverse	Reverse
		$0.01	19.00 mm	1.55 mm	3.11 g	copper 95% tin/zinc 5%1	Plain	Abraham Lincoln	Wheat	1909	wide2	Wheat Penny, Penny, Cent
		$0.01	19.05 mm		2.50 g	core: zinc 97.5% plating: copper 2.5%1			Lincoln Memorial	1959	wide
		$0.05	21.21 mm	1.95 mm	5.00 g	copper 75% nickel 25%3	Plain	Thomas Jefferson	Monticello	1938	wide	Nickel
see article: Westward Journey nickel		$0.05							Westward Journey Series	2004
		$0.05							Monticello	2006
		$0.10	17.91 mm	1.35 mm	2.268 g	copper 91.67% nickel 8.33%4	118 reeds	Franklin D. Roosevelt	Torch, oak branch, olive branch	1946	wide	Dime
		$0.25	24.26 mm	1.75 mm	5.67 g		119 reeds	George Washington	Bald eagle	1932 (resumed in 1977)5	wide	Quarter
		$0.25							Bicentenial colonial military drummer	(1975) 19765
	See article: 50 State Quarters	$0.25							State Quarter Series	1999
		$0.50	30.61 mm	2.15 mm	11.34 g		150 reeds	John F. Kennedy	Seal of the President of the United States surrounded by 50 stars	1964 (resumed in 1977)5	limited6	Half dollar, 50-cent piece
		$0.50							Independence Hall	(1975) 19765
		$1	26.50 mm	2.00 mm	8.10 g		reeded	Susan B. Anthony	Apollo 11 mission insignia	1979 (resumed in 1999)8	limited6	SBA, Suzie B.
		$1	26.50 mm	2.00 mm	8.10 g	copper 77% zinc 12% Manganese 7% nickel 4%	plain	Sacagawea	Bald Eagle in flight	2000	limited6	Gold(en) dollar, Sacajawea, Sackies
see article: Presidential $1 Coin Program7		$1					Plain w/ incused inscriptions	Each deceased president	Statue of Liberty	2007	limited	Gold(en) dollar

Remarks

1. The mass and composition of the cent changed to the current copper plated zinc core in 1982. Both types were minted in 1982 with no distinguishing mark. Cents minted in 1943 were struck on planchets punched from zinc coated steel which left the resulting edges uncoated. This caused many of these coins to rust. These "steel pennies" are not likely to be found in circulation today, as they were later intentionally removed from circulation for destruction.
2. The wheat ear cent was mainstream during its time. Some dates are rare, but some can still be found in circulation.
3. Nickels produced from mid-1942 through 1945 were manufactured from 56% copper, 35% silver and 9% manganese. This allowed the saved nickel metal to be shifted to industrial production of military supplies during World War II.
4. Prior to 1965 and passage of the Coinage Act of 1965 the composition was 90% silver and 10% copper. The half-dollar continued to be minted in a 40% silver-clad composition between 1965 and 1970. Dimes and quarters from before 1965 and half-dollars from before 1971 generally don't remain in circulation due to being removed for their silver content.
5. In 1975 and 1976 bicentennial coinage was minted. Regardless of date of coining, each coin bears the dual date "1776-1976".
6. Use of the Kennedy half-dollar, Susan B. Anthony and Sacagawea dollars is not as widespread as that of other coins in general circulation; most Americans use quarters, dimes, nickels and pennies only. Coins are minted for general release through banks and other financial institutions, and are also available for collectors in uncirculated rolls, mint sets and proof sets from the United States Mint.
7. The Presidential Dollar series will feature portraits of all deceased U.S. Presidents with four coin designs issued each year in the order of the president's inauguration date. These coins began circulating on February 15, 2007.
8. The Susan B. Anthony dollar coin was minted from 1979-1981 and 1999. The 1999 minting was in response to Treasury supplies of the dollar becoming depleted and the inability to accelerate the minting of the Sacagawea dollars by a year. 1981 Anthony dollars can sometimes be found in circulation from proof sets that were broken open, but these dollars were not minted with the intent that they circulate.

Bullion coins

Non-circulating bullion coins have been produced each year since 1986. They can be found in silver, gold and also platinum since 1997. The face value of these coins is symbolic and does not actually reflect the value of the precious metal contained therein.

Type	Diameter	Fineness	Face Value	Content
American Silver Eagle	40.6 mm	999 fine silver	$1	1.00 troy ounce (~31.10 grams)
American Gold Eagle	16.5 mm 22.0 mm 27.0 mm 32.7 mm	916 fine gold (22 karat)	$5 $10 $25 $50	0.10 ozt (~3.11 g) 0.25 ozt (~7.78 g) 0.50 ozt (~15.6 g) 1.00 ozt (~31.10 g)
American Platinum Eagle	16.5 mm 22.0 mm 27.0 mm 32.7 mm	999.5 fine platinum	$10 $25 $50 $100	0.10 ozt (~3.11 g) 0.25 ozt (~7.78 g) 0.50 ozt (~15.56 g) 1.00 ozt (~31.10 g)
American Buffalo	32.7 mm	999.9 fine gold (24 karat)	$50	1.00 ozt (~31.10 g)

Commemorative coins

Modern commemoratives have been minted since 1982. A complete list is available: Modern United States commemorative coins.

Composition of US Modern Commemorative Coins

Type	Total Weight	Diameter	Composition	Precious Metal Content
Half Dollar	11.34 g	30.61 mm (1.205 in)	Cu 92%, Ni 8%	none
Dollar	26.73 g	38.1 mm (1.50 in)	Ag 90%, Cu 10%	silver 24.057 g (~0.773 ozt)
Half Eagle	8.359 g	21.59 mm (0.850 in)	Au 90%, Ag 6%, Cu 4%	gold 7.523 g (~0.242 ozt)
Eagle	16.718 g	26.92 mm (1.06 in)	Au 90%, Ag 6%, Cu 4%	gold 15.05 g (~0.484 ozt)
First Spouse Eagle Bullion	14.175 g	26.49 mm (1.043 in)	Au 99.99%	gold 14.175 g (~0.456 ozt)

Obsolete coins

• Half cent: $0.005, copper
• Large Cent: $0.01, copper
• Two-cent piece: $0.02, copper
• Three-cent piece: $0.03, silver and copper-nickel
• Half dime: $0.05, silver
• Twenty-cent piece: $0.20, silver
• Silver dollar: $1.00, silver (some modern commemoratives are minted in this denomination)
• Gold dollar: $1.00, gold
• Quarter-eagle: $2.50, gold
• Three-dollar piece: $3.00, gold
• Stella: $4.00, gold (not circulated)
• Half-eagle: $5.00, gold (some modern commemoratives are minted in this denomination)
• Eagle: $10.00, gold (some modern commemoratives are minted in this denomination)
• Double eagle: $20.00, gold, discontinued in the 1930s
• Half-union: $50.00 (Commemorative only, California territorial gold, pattern piece)

Note: It is a common misconception that "eagle"-based nomenclature for gold U.S. coinage was merely slang. This is not the case. The "eagle," "half-eagle" and "quarter-eagle" were specifically given these names in the Coinage Act of 1792. Likewise, the double eagle was specifically created as such by name ("An Act to authorize the Coinage of Gold Dollars and Double Eagles", title and section 1, March 3, 1849).

Some modern commemorative coins have been minted in the silver dollar, half-eagle and eagle denominations.

See also US coin sizes, showing all major US coin series and scaled images in a single chart.

The law governing obsolete, mutilated, and worn coins and currency, including denominations which are no longer in production (i.e. Indian cents) can be found in 31 USC 5120.

Criticisms

The values of current US coins are not inscribed in numerals on the coin. Instead the value is written in English words, presenting potential difficulties for visitors to the country who do not speak the language well or English speakers unfamiliar with the currency. Furthermore, the coins' inscriptions do not follow a pattern in describing the value: "One Cent" (1 cent), "Five Cents" (5 cents), "One Dime" (10 cents), "Quarter Dollar" (25 cents), and "Half Dollar" (50 cents).

For historical reasons the size of the coins does not increase with their face value. Both the one cent and the five cent are larger than the ten cent and the less common 50 cent coin is larger than the recent Sacagawea and Susan B. Anthony dollar coins, and the newer same sized Presidential $1 Coins. The sizes of the dime, quarter, and half dollar are holdovers from before 1965 when they were made from 90% silver and 10% copper; their sizes thus depended upon the amount of silver needed to equal the face value. The diameter of the current dollar coins was introduced in 1979 with the Susan B. Anthony dollar not only as a concession to the vending machine industry which wanted a smaller dollar coin usable in their machines but also as an increase in the amount of seigniorage for the US Government (the difference between what a piece of money costs to produce and its face value or the "profit margin").

External links

• United States Mint
• United States Virtual Coin Museum
• Page of 1792 Mint and Coinage Act (Describes the first completely regulated U.S. coinage system.)
• What have they done to our coins? - An article visually exploring recent changes to U.S. modern coin designs.
• Complete US Coin Histories By year and type.
• U.S. Coin webpage