United SC

United SC was originally established in 1927 as Eveready Association Club. Since then, they participated in fewer editions of the Calcutta Football League. The club has a tradition of bringing up local and unknown talents from various parts of Bengal. In 2003, they lifted their first trophy All Airlines Gold Cup, defeating Mohun Bagan 2–1. In 2004, they emerged victorious in the Sikkim Governor's Gold Cup, defeating ANFA XI in final by 4–2 in penalty-shootout, after the game ended 1–1. During the 2005–06 season, they participated in Kalinga Cup in Odisha and reached the final, defeating Bangladeshi side Badda Jagoroni Sangsad by 4–2. They clinched the title defeating Cuttack SSH 2–0. Eveready Association also reached the final of the 111th edition of IFA Shield but lost 1–5 to Bayern Munich II at the end.

In 2006, the club was renamed as United Sports Club to attract a title sponsor and the football division owned by United Sport Football Team Private Ltd. Later, veteran manager Amal Dutta was roped in as head coach in place of Belgian Philippe De Ridder. With the inflow of sponsorship, the club clinched promotion to the first division of the I-League in 2007. Previously the club has competed in the National Football League (India) before joining the newly formed I-League. Later in 2009, they roped in Subrata Bhattacharya as head coach.

Prayag United participated in the 123rd edition of the Durand Cup in 2010. United emerged champion at the Ambedkar Stadium with a 1–0 tie-break win over JCT FC. For the 2010–11 I-League season, United SC played at the Salt Lake Stadium in Kolkata. On Indian Transfer deadline day United SC made headline news by signing India national football team striker Sunil Chhetri until the end of the season. On 3 April 2011, Chhetri scored his first goal for Chirag United against Dempo, however, Dempo won the match 4–2. Chhetri then scored a brace on 29 April 2011 against ONGC to help salvage a 2–2 draw for Chirag. In June 2011 after the I-League season ended, old sponsors Chirag chose to cut ties with United SC and thus Chirag United SC became Prayag United Sports Club. Even though the team has lost a lot in terms of sponsorship money the club is still able to sign and retain their current players.

On 3 August 2011, it was announced that United Sports Club had signed a sponsorship deal with Prayag Group and on 7 August 2011 United Sports Club officially changed their name to Prayag United SC. In October, the club narrowly missed the opportunity of winning the Durand Cup, after a 5–4 defeat to Churchill Brothers. The association, however was cancelled in the summer of the 2013, when the company found itself involved in the chit-fund scam. The name was again changed to United Sports Club.

In November 2012, Dutchman Eelco Schattorie was roped in by the club as their new manager, and he managed his first game in India on 10 November 2012, where he led Prayag to a 10–1 victory over newly promoted United Sikkim. Schattorie won his first and only cup for the side on 20 March 2013 when Prayag United defeated East Bengal in the IFA Shield final 1–0 through a Ranti Martins goal. The following season in the I-League, They thrashed Air India FC by 5–1 margin, and eventually finished the 2012–13 campaign leading Prayag United to a fourth-place finish with 44 points. In that season, they emerged as the runners-up of the 2012 IFA Shield, losing to East Bengal by 4–2 on penalties.

In 2013, the club won their maiden IFA Shield title by defeating East Bengal FC in the final by 1–0 margin. In that competition (Semi-finals), they also defeated a foreign side Deportivo Saprissa of Costa Rica. After the end of 2013–14 I-League season, United finished on tenth position with 26 points in 24 matches and was evicted from I-League for not fulfilling the Asian Football Confederation's club licensing criteria.

On 24 July 2015, it was announced that the club appointed Bino George as the new head coach. United emerged as champions in the 2019–20 Calcutta Premier Division B with 28 points in 14 matches and earned promotion to Division A. In that season, United reached to the semi-finals of the 2020 IFA Shield but lost to George Telegraph SC by 2–1.

United SC maintained good form in domestic league, as they moved to championship round of 2022–23 I-League 2. At the end of the round in May, they finished in fifth position. In June 2023, the Indian Football Association (IFA) announced the merger of both Premier Division A and B of the Calcutta Football League, ahead of its 125th edition, in which United was allowed to compete in Group I. In 2023–24 I-League 2, the club was managed by Ranjan Bhattacharjee. In that league season, United SC earned sixth-place finish with 15 points in 14 matches. In 2024–25 season, the club stayed and took part in the I-League 2.