Billingham Synthonia

The club was established in 1923 and was named after an agricultural fertiliser, Synthonia being a contraction of "synthetic ammonia", a product manufactured by ICI, with which the club was affiliated. They initially played in the South Bank & District League, later joining the Teesside League. They won the Teesside League Cup in 1934–35, the league title in 1936–37 and the League Cup for a second time in 1938–39.

In 1945 the club joined the Northern League. They reached the first round of the FA Cup for the first time in 1948–49, losing 5–0 to Crewe Alexandra at Gresty Road. The following season saw them finish as Northern League runners-up and reach the first round of the FA Cup again, this time losing 3–0 at Stockport County. After finishing as runners-up again in 1950–51, a season in which they did not concede a goal during their home league matches, the 1951–52 season saw them win the League Cup with a 1–0 win over Tow Law Town in a replay, finish as runners-up for the third consecutive season and reach the FA Cup first round for a third time, losing 5–0 at Scunthorpe & Lindsey United. They won the Northern League for the first time in 1956–57, a season which also saw another FA Cup first round appearance, resulting in a 6–1 defeat at Carlisle United. The following season they reached the first round again, losing 5–2 at Boston United.

In 1985–86 the club were relegated to Division Two after finishing second-from-bottom of Division One. However, they made an immediate return to Division One by winning Division Two at the first attempt. The 1987–88 season saw a second League Cup win with a 2–1 defeat of Shildon in the final, as well as another FA Cup first round appearance – a 4–2 loss to Halifax Town in a home match played at Hartlepool United's Victoria Park. They went on to win back-to-back Division One titles in 1988–89 and 1989–90; The 1989–90 season also saw a third League Cup win, beating Whitby Town 5–2 in the final, as well as a seventh appearance in the FA Cup first round, this time losing 1–0 at Lincoln City.

A fourth Northern League title was won in 1995–96. In 2006–07 Billingham reached the semi-finals of the FA Vase; after beating AFC Totton 2–1 away from home, they lost the home leg 2–1, with Totton winning the penalty shootout 5–4. At the end of the 2014–15 season they were relegated to Division Two after finishing in the Division One relegation zone. A third-place finish in 2016–17 saw them promoted back to Division One. However, in 2017–18 the club finished bottom of Division One and were relegated back to Division Two.