The late 1800s saw the bustling port town of Portishead thrive with the expansion of its pier, docks, and railway system, attracting many prominent figures to the area. It was only natural that a Masonic Lodge would be established in this thriving community, and thus, Eldon Lodge was born.

Consecrated in September 1878, the Lodge held its meetings at the Royal Hotel and quickly grew in numbers, thanks to the improved accessibility provided by the railway link to Bristol and the light railway to Weston, Clevedon, and Portishead. By 1890, the Lodge had 33 members and by five years after its consecration, the membership had grown to 72.

During World War I, several brethren of Eldon Lodge fought and sacrificed their lives for their country, while the remaining members supported the war effort. In 1933, the Lodge purchased the old GWR Railway office and held its first meeting in the new building that July.

Throughout its 145-year history, Eldon Lodge has been dedicated to supporting the local community, especially during the Christmas season, when gifts were given to the poor and needy of Portishead and Pill. This tradition continues to this day through charitable donations to local organisations.

After WWII, Freemasonry and Eldon Lodge in particular experienced a surge in membership as servicemen returned home seeking to continue the camaraderie they had experienced during their service. The Lodge reached its peak membership of 164 in 1944.

Since the early 20th century, several members have attained long service of over 50 years and become "Masonic Veterans."

Eldon Lodge has a rich maritime history, being located in close proximity to the sea in Portishead, and many members earned their livelihoods from the sea. The old GWR building was sold to the RNLI, and a new lifeboat station was built in its place. The Lodge currently meets at Clevedon Masonic Hall along with five other lodges, and its affiliation with the sea remains strong. The Lodge's traditional "Eldon Song," written by a long-standing member who played the organ at meetings, is fittingly inspired by an old sea shanty.

Eldon Lodge has been home to many notable members, including the Weatherly family, well-known in Portishead for the works of Fred Weatherly, including the famous song "Danny Boy."

BS Thomas, a member of Eldon Lodge since 1922, served as a Political Officer in the forces posted to Jordan in 1922, and went on to become the Finance Minister and advisor to the Sultan of Muscat and Oman. He was the first European to cross the Rub Al Khali desert on his own camel, and was awarded the OBE and the CMG for his service to his country.

William Kingdon Thomas, another prominent member, was known as the "Father of the Lodge" for his dedication and support over many years. He was the father of both Eldon Lodge and Royal Clarence Lodge in Bristol, and a founding member of the Charles Dickens Society in Bristol.