The military of the United States has used many different types of hand grenades since its foundation.

High explosive, fragmentation, and blast Mk I The Mk 1 grenade was introduced in 1917 during World War I. A multistep arming process on the device resulted in many failures, and as a result it was replaced in 1918 by the Mk II.

Mk II and Mk IIA1 More commonly known as the Pineapple, the Mk II series (also written Mk 2) was the most commonly used US fragmentation grenade of the Second World War. The Mk II had a grooved exterior originally intended to aid fragmentation of the grenade. However, later studies showed that this design has no effect on fragmentation, though it does provide a non-slip surface that improves grip. The filling was either EC blank fire powder (approximately . smokeless small arms powder) or flaked TNT (approx. ). TNT became the common filler from 1942 onwards.Inert-Ord.net. American Mk.II Hand Grenade , 2 April 2006.Access date: 18 April 2007.Vilinsky, Alan. WWII US Army Reenactment Association, Hand Grenades , 19 August 2006. Access date: 18 April 2007.

The Mk II was also available in a little-known HE-Blast variant (better known as the concussion), and a combined effect HE-Frag variant. This was largely superseded by the Mk III series. The Mk IIA1 (also written Mk 2A1) used the M10A2 or M10A3 fuses, upgrades to the previous M10A1 fuse used in the Mk II.Hogg 2001, p. 327. Later reissued Mk II variants featured the modern M204 series fuse.Gervasi 1984, p. 305.

Mk III, Mk IIIA1, and Mk IIIA2 Unlike the Mk II, the Mk III (also written Mk 3) was a cylindrical grenade designed to be used as an offensive weapon for clearing rooms, trenches, and other enclosed spaces. A concussion grenade, the Mk III series, was designed to incapacitate through the pressure and impulse produced by the explosion. The MkIII had a far larger TNT filling than the Mk II series, up to of TNT, in comparison to. Although a minimum-fragmentation grenade, large fragments (most likely the fuse assembly or surrounding material) could be projected as far as from the detonation point. The differences between the Mk III, the Mk IIIA1 (also written Mk 3A1), and the Mk IIIA2 (also written Mk 3A2) were improved versions of the M6 fuse: the Mk III featured the M6/A1, the Mk IIIA1 the M6A2, and the Mk IIIA2, the M6A3. Later reissued Mk III variants featured the modern M206 series fuse.

M26/A1/A2, M57 and M61 The M26 series is in many ways an upgrade to the basic principle of the Mk II: a similarly shaped, but not visibly ribbed, fragmentation grenade. The M26 has a filling of Composition B contained within a sheet steel two-part outer shell that covers a pre-notched fragmentation coil inner liner. The use of the inner liner creates a highly predictable fragment pattern and casualty radius. The grenade was found to have problems with incomplete detonation of the filler, and the M26A1 featured a tetryl booster to ensure complete detonation.Dockery 1997, p. 173. The M61 grenade was the product of a further Product Improvement Program (PIP), and is identical to the M26A1 with the exception of the additional safety clip for the spoon of the grenade on the M61. The M26A2 is identical to the M26A1, except for being fitted with the M217 impact fuse.ORDATA Online.U.S. GRENADE, HAND, FRAG, M26A2 & M57 . Access date:18 April 2007. The M57 is the equivalent of the M61 for the M26A1, and is the same as the M26A2 with the exception of the additional safety clip on the spoon of the grenade.Gervasi 1984, p. 304.

M33, M33A1/M59, M67, and M68 Similar in format to the M26, the M33 is a spherical fragmentation grenade also filled with Composition B explosive. Unlike the M26, the inner wall is prescored and does not contain a fragmentation coil.Dockery 1997, p. 175. The grenade has a smooth surface, unlike the Mk II series "pineapple" casing. The M67 was part of a similar PIP and is identical to the M33, with the exception of the additional safety clip for the spoon of the grenade on the M67. Early M33 grenades were also more of an oval shape before transitioning over to the more spherical shape of the M67. The M67 is the current issue HE-Frag grenade for the US military. The M33A1 is the impact version of the M33, using the M217 electrical impact fuse in place of the normal delay fuze. At an unknown time the M33A1 was redesignated as the M59.ORDATA Online. U.S. GRENADE, HAND, FRAG, M59 & M68 . Access date:18 April 2007. There should be no difference between these grenades except that the M33A1 may be more ovular in shape than the more spherical M59. The M68 is the same as the M59, with the exception of the additional safety clip.Gervasi 1984, 305.

Mk 21 Mod 0 Scalable Offensive Hand Grenade

In 2010, US SOCOM began fielding the Mk 21 Mod 0 Scalable Offensive Hand Grenade that delivers blast effects. The grenades are "stackable," meaning up to three can be connected to increase blast power.

The base grenade has a non-removable, 3.5 second fuse and a body encasing of high explosive, so three connected grenades can have up to of blast force.Army Testing Stackable Grenades for Infantry - Kitup.Military.com, 20 February 2015U.S. Army Tests Soviet-Designed Rocket Launcher - Kitup.Military.com, 18 February 2015RPGs, grenades and dummies: 9 soldier-tested gadgets - Armytimes.com, 6 April 2015

ET-MP

Picatinny Arsenal is developing the Enhanced Tactical Multi-Purpose (ET-MP) hand grenade to combine fragmentation and concussive effects in a single weapon. The grenade fills the gap left by the withdrawal of the MK3A2 concussion grenade from service in 1975. The MK3A2 was used to clear bunkers by detonating in confined spaces where blast pressure would reverberate off the walls. However, the exterior coating of the MK3A2 contained up to 50% asbestos, which can be hazardous to troops when inhaled. The M67, introduced in 1968, was left as the only anti-personnel grenade in the inventory. The ET-MP allows soldiers to choose between fragmentation and blast overpressure effects by flipping a switch. It also has improved safety, being the first Insensitive Munitions-qualified lethal grenade in the Army's portfolio with an electronic fuse, or delay mechanism, instead of a mechanical fuse, that can be narrowed down into milliseconds and will not be able to detonate until armed. The grenade is designed for ambidextrous use, whereas the M67 required a different procedure for left-handed use. Research for the ET-MP grenade began in 2010, with entry expected in 2020,ARDEC develops next generation of hand grenade - ARDEC.Army.mil, 15 September 2016The U.S. Army Designs a New Hand Grenade After More Than 40 Years - Warisboring.com, 17 September 2016 however it has not been adopted.

M111

In 2021 the US Army adopted the M111 Offensive Hand Grenade for blast overpressure and concussion effects in enclosed areas. The M111 will replace the Mk3A2 (Mk IIIA2).TC 3-23.30 Grenades and Pyrotechnic Signals 2023. Archived.

Smoke and signaling grenades

M1 Frangible Grenade (FS)

In September 1942, the United States standardized a Molotov cocktail-style device that was nominally designated as a "grenade". It consisted of a pint-sized clear glass bottle with a crimped metal cap. It was dubbed "frangible" because it was made of glass, which is brittle and easily broken.

Most fillers were liquid compounds selected because they were activated by exposure to the air, thus not requiring a detonator. FS was a mixture of sulfur trioxide and chlorosulfuric acid that created a heavy, acrid screening smoke.

The M1 Frangible Grenade (FS) was declared limited standard by 1944.

M8, M83 and Model 308-1 White Smoke A smoke grenade similar visually to the Mk III HE-Blast grenade, the M8 (also written AN/M8) is filled with hexachloroethane (HC), a chemical agent that produces a thick white smoke when burned. The M8 is used for signaling and screening purposes, and since it works by burning the HC for its effect, it can also be used as an improvised incendiary device.Dockery 1997, p. 179. HC smoke is toxic and can cause more serious health problems with prolonged exposure. The M83 (also written AN/M83) is a modernized version of the M8, using TA (Terephthalic Acid) instead of HC as the filler mixture.Cooke, Gary W. Gary's Olive Drab Page, Hand Grenades . Access date:18 April 2007. The Model 308-1 White Smoke was a modified version of the M8 produced at the Special Operations Branch of the Naval Weapons Center at China Lake California, often simply referred to as China Lake. The Model 308-1 was modified for a US Navy SEAL requirement with a greater burning rate, meaning a greater smoke output but a shorter overall burning time.Dockery 1997, p. 185.

M15, M16, and M34 The M15 is a white phosphorus smoke grenade, nicknamed Willie Peter or Willie Pete (for white phosphorus), used for screening and signaling purposes. It is cylindrical, but with rounded edges compared to those of the M8.Dockery 1997, p. 177.ORDATA Online.U.S. GRENADE, SMOKE, WP, M15 AND FUZES, M6A3, M10A3, & M200A1 . Access date:18 April 2007. WP has many of the same properties as HC and is also burned to create the effect, giving the M15 a similar incendiary capability. The M16 was a colored version of the grenade that was originally available in red, orange, yellow, green, blue, violet, and black smoke versions. This was later simplified to red, yellow, green, and violet. The M34 grenade was a variant of the M15 designed to be usable as a rifle grenade using the M2 series of grenade launching adapters, and was ribbed to give the fins better grip on the grenade body.

M18

Designated standard issue on 24 September 1943. A purpose-designed smoke flare, the M18 was a smoke grenade visually similar to the M8, but with a different type of filler and internal construction. The M18 has been the primary colored smoke grenade of the United States Armed Forces since its introduction, being used extensively. The M18 is produced with four colors of smoke: green, yellow, red, and violet. A non-submersible variant of the M18 with a flotation bladder was made in 1971, for use in marking at sea. This version of the M18 did not see usage outside of testing however. It was produced by Northrup Carolina, a subsidiary of Northrup Grumman at the time.ORDATA Online.U.S. GRENADE, HAND, SMOKE, NONSUBMERSIBLE . Access date:18 April 2007.

XM48/E1/E2/E3 A variant of the XM47 series, which is in the following section, the XM48 is a skittering-type smoke grenade: the filler is burned internally and vented through ports in the grenade body, making the grenade spin erratically. The XM48 series burns an unknown filler for a red-colored smoke, probably WP or HC based, and is not known to be standardized.ORDATA Online.U.S. GRENADE, HAND, RED SMOKE, M48E1 (OBSOLETE), & M48E3 . Access date:18 April 2007.

Mk 1 Mod 0/1/2/3 An illumination grenade, with a magnesium filler ignited by a wick type fuze, the Mk 1 Mod 0 was first produced during the Second World War. The Mod 1 probably featured an improved type fuze, moving away from the simple wick lighter design. The Mod 2 featured a simplified overall design, while the Mod 3 replaced the single-piece steel body with a two-piece plastic shell.Dockery 1997, p. 187.Inert-Ord.net.U.S. Mk.I Illumination Grenade (WWII) , 2 April 2006. Access date:18 April 2007.

EX 1 Mod 0 and EX 2 Mod 0