The United States intervention in Syria is the United States-led support of Syrian opposition and Rojava during the course of the Syrian civil war and active military involvement led by the United States and its allies – the militaries of the United Kingdom, France, Jordan, Turkey, Canada, Australia and more – against the Islamic State of Iraq and the Levant (ISIL) and al-Nusra Front since 2014. Since early 2017, the U.S. and other Coalition partners have also targeted the Ba'athist government in Syria and its allies via airstrikes and aircraft shoot-downs.

2014 September 2014: Airstrikes begin

On 22 September 2014, Pentagon Press Secretary Rear Admiral John Kirby confirmed that the United States and partner nations had undertaken airstrikes in Syria using fighters, bombers, and Tomahawk missiles in strikes authorized by President Barack Obama. The initial strikes were coordinated by United States Central Command (USCENTCOM) with Arab partner forces from Bahrain, Jordan, Qatar, Saudi Arabia, and the United Arab Emirates (UAE) conducting or supporting airstrikes. The overnight strikes targeted about 20 Islamic State of Iraq and the Levant (ISIL) targets, including headquarters buildings. Sources in Syria claimed that among the target locations was Brigade 93, a Syrian army base that ISIL militants had recently captured, and targets in the ISIL-held towns of Tabqa and Tell Abyad in Raqqa Governorate. The U.S. also targeted the al-Qaeda-affiliated al-Nusra Front and the Khorasan group in Syria's Aleppo and Idlib provinces. At least 70 Islamic State fighters, 50 fighters affiliated with al-Qaeda, and eight civilians were killed overnight by the airstrikes, according to the Syrian Observatory for Human Rights (SOHR) conflict monitor, while eight strikes were launched against the Khorasan group.

U.S. F-22 Raptor stealth fighters were reportedly among the U.S. aircraft striking targets in Syria on the first night of the campaign, carrying out their first ever combat missions since entering service in 2005. Syrian military radar was "passive" during the first air strikes, making no known attempt to counter coalition aircraft. The U.S. had deployed HARM missiles as a precaution, as it was uncertain how Syria's air-defense network would react.

On 24 September, the U.S.-led coalition conducted a second round of airstrikes on Islamic State facilities in Syria, targeting ISIL-held oil production facilities the group was using to fund their activities. Some targets were apparently also mobile production facilities which were most likely not refineries. In a third round of airstrikes on ISIL targets on 25 September, Arab partners led the U.S. in strikes against militant-held oil facilities in northeastern Syria. Saudi Arabia and the UAE dropped 80 percent of the bomb tonnage in the third round of strikes, compared to other strikes in which the U.S. led the way. On 26 September, the U.S. carried out a fourth round of airstrikes on ISIL targets in eastern Syria, targeting ISIL heavy equipment and destroying four battle tanks in Deir ez-Zor Governorate.

In a fifth round of airstrikes on 27 September, the U.S. led strikes along with Saudi Arabia, Jordan and the UAE against ISIL forces in the Kobanî Canton of Syrian Kurdistan, destroying two armored vehicles and an unknown number of fighters. The area was under siege by ISIL militants, with the fighting forcing over 100,000 Syrian Kurds to flee across the border to Turkey.

On 28 and 29 September, the U.S. carried out two rounds of strikes against ISIL positions across four provinces. Among the facilities targeted was the entrance to the largest gas plant in Syria, in Deir ez-Zor Governorate, and ISIL training camps and vehicles near an ISIL-controlled grain silo in Manbij.

October 2014 In an eighth round of airstrikes on 1 October, the U.S.-led coalition conducted daytime strikes against Islamic State forces besieging the primarily Kurdish town of Kobanî. The strikes were in support of the Free Syrian Army (FSA) and the Kurdish People's Protection Units (YPG), who were defending the city. On 2 October, the U.S. and the UAE led a ninth round of strikes against ISIL forces across Syria, destroying an ISIL checkpoint near Kobanî, damaging a tank north of the Sinjar Mountain area, destroying a tank west of Raqqa, and destroying several ISIL facilities east of Aleppo.

In a tenth round of airstrikes on 3 October, the U.S., assisted by Saudi Arabia and the UAE, struck ISIL forces in northern and eastern Syria, destroying an ISIL garrison south of al-Hasakah, destroying two tanks southeast of Deir ez-Zor and two modular oil refineries and a training camp south of Raqqa, and striking an ISIL building northeast of Aleppo.

The U.S. led an 11th round of airstrikes on 4 October, alongside Jordan, Saudi Arabia, and the UAE, against ISIL forces across Syria. The coalition carried out nine strikes, destroying an ISIL infantry unit, armored personnel carrier (APC), and a vehicle south of Kobanî. They also destroyed a tank and a vehicle southeast of Deir ez-Zor, damaged the Tabqa airfield and destroyed an artillery piece near Raqqa, as well as an ISIL depot and logistics complex south of al-Hasakah. In a 12th round of strikes on 5 October, the U.S. carried out three airstrikes against ISIL forces in central and eastern Syria, destroying an ISIL bulldozer, two ISIL tanks and another vehicle northwest of Mayadin, along with six firing positions and a large ISIL unit northwest of Raqqa.

On 6 October, the U.S. carried out a 13th round of strikes, destroying an ISIL tank near Tabqa airfield west of Raqqa, two fighting positions south of Kobanî, and a tank southeast of Deir ez-Zor. On 7 October, in a 14th round of strikes, the U.S., Saudi Arabia and the UAE, carried out nine strikes damaging multiple ISIL-controlled buildings west of al-Hasakah, damaging a staging area and IED production facility northeast of Deir ez-Zor, destroying three armed vehicles, damaging one armed vehicle, destroying a vehicle carrying anti-aircraft artillery, destroying an ISIL tank, and an ISIL unit in and around Kobanî, and killing a small group of fighters southwest of Rabiyah.

On 8 October, the U.S. led a 15th round of nine airstrikes along with the UAE, destroying an armored personnel carrier, four armed vehicles, an artillery piece, and damaged another armed vehicle in and around Kobanî, striking an ISIL training camp and fighters northwest of Raqqa, and destroying a tank northwest of Deir ez-Zor.

In a 16th round of airstrikes in Syria on 9 October, the U.S. carried out nine airstrikes in the areas in and around the besieged border town of Kobanî. The U.S. carried out six airstrikes south of Kobanî that destroyed two ISIL-held buildings, one tank and one heavy machine gun along, a fighting position along with one large and two small ISIL units. North of Kobanî, the U.S. struck two small ISIL units and destroyed two ISIL-held buildings.

On 10 October, the U.S. led a 17th round of airstrikes along with Saudi Arabia and the UAE, carrying out nine strikes that destroyed two ISIL training facilities, three vehicles, damaging a tank and striking two ISIL units in and around Kobanî. The strikes also destroyed an armored vehicle staging facility east of Deir ez-Zor and struck a small ISIL unit northeast of al-Hasakah.

In an 18th round of airstrikes in Syria on 11 October, the U.S. carried out six airstrikes in and around Kobanî. The U.S. carried out four strikes north of Kobanî striking a fighting position, damaging a command and control facility, destroying a staging building, and striking two small ISIL units. South of Kobanî, two airstrikes destroyed three trucks.

On 12 October, the U.S. led a 19th round of airstrikes along with Saudi Arabia and the United Arab Emirates, carrying out four strikes – three in Kobanî, destroying a fighting position and a staging area, and one strike northwest of Raqqa, destroying an armored vehicle compound. Also on 12 October, the U.S. announced that the Turkish government had approved the use of Turkish military bases by Coalition forces fighting ISIL in Syria and Iraq. These installations included key bases only from the Syrian border and important U.S. military bases in Turkey such as the Incirlik Air Base. Despite the announcement of Turkish government approval, on 13 October, Turkish officials publicly denied that any agreement had been made over Coalition use of Turkish airbases, including Incirlik.

In a 20th round of airstrikes in Syria on 13 October, the U.S. and Saudi Arabia carried out eight airstrikes against ISIL forces. Seven of the strikes were in and around Kobanî, striking a large ISIL unit, two small units; damaging one staging location and destroying another, destroying a heavy-machine-gun firing position, destroying three buildings, and damaging two others. One other strike northwest of Raqqa struck an ISIL garrison.

On 14 October, the U.S. and Saudi Arabia carried out the 21st round and the largest set of strikes against ISIL in Syria since the beginning of the intervention, with 21 strikes against targets in and around Kobanî, and an additional strike near Deir ez-Zor. According to the Department of Defense, the strikes were designed to interdict ISIL reinforcements and resupply zones and prevent ISIL from massing combat power on the Kurdish-held portions of Kobanî. The strikes destroyed two staging locations and damaged another, destroyed one ISIL building and damaged two others, damaged three ISIL compounds, destroyed one truck, one armed vehicle, and one other vehicle near Kobanî in support of Kurdish forces resisting the |siege of the town. In addition to those targets, the airstrikes struck seven staging areas, two mortar positions, three ISIL occupied buildings, and an artillery storage facility. An additional strike near Deir ez-Zor struck a modular oil refinery.

In a 22nd round of airstrikes on 15 October, the U.S. carried out 18 strikes against ISIL targets in and around Kobanî. The strikes destroyed multiple fighting positions and also successfully struck sixteen ISIL-occupied buildings.

On 16 October, the U.S. carried out a 23rd round of airstrikes with 14 airstrikes against ISIL targets in and around Kobanî striking 19 ISIL-controlled buildings, two command posts, three fighting positions, three sniper positions, one staging location, and one heavy machine gun position.

In a 24th round of airstrikes on 17 October, the U.S. carried out seven airstrikes against ISIL targets in and around Kobanî and in north-eastern Syria. Six airstrikes took place near Kobanî, striking three ISIL-controlled buildings; they also destroyed two fighting positions, suppressed three fighting positions, and destroyed two vehicles. One other airstrike near Al-Shaddadi struck ISIL-controlled oil collection equipment, including several petroleum, oil, and lubricants tanks, and a pump station.

On 20 October, the U.S. carried out a 25th round of airstrikes, with six airstrikes against ISIL targets in and around Kobanî. The strikes destroyed ISIL fighting positions, ISIL mortar positions, a vehicle, and one stray equipment supply bundle from a U.S. airdrop of Kurdish supplies in order to prevent the supplies from being captured.

In a 26th round of airstrikes on 21 October, the U.S. carried out four airstrikes against ISIL targets in and around Kobanî. The strikes destroyed several ISIL fighting positions, an ISIL-controlled building, and a large ISIL unit. The British Royal Air Force began operating over Syria in a surveillance role on the same date, making the UK the first Western country other than the U.S. to operate in both Iraq and Syria simultaneously.

On 22 October, the U.S. carried out a 27th round of airstrikes with six airstrikes against ISIL targets in and around Kobanî. The strikes destroyed several ISIL fighting positions, two ISIL vehicles, an ISIL-controlled building and an ISIL logistical center.