The town was named after Captain Zachary Gillam and his son, Benjamin. They were 17th century fur traders on Hudson's Bay. They sailed on the vessel, "NONSUCH", whose replica can be found in Winnipeg's Museum of Man and Nature. They remained in the region from 1668-1670 for the fur trade and to obtain land rights. This mission was supported by the Royal Society of England and resulted in the incorporation of the Hudson's Bay Company on May 2, 1670.
The first settlement in the Gillam area started in 1912-13, four miles east from the present town site at Mile 330. It had a population of nearly 350 people, consisting of railway workers and families. When the railroad reached the Kettle Rapids on the Nelson River, they began the construction of a bridge across it. However, it's construction was interrupted by World War One. Still today, the foundations of shacks where the surveyors lived can be seen in the bush 100 yards downstream from the railway bridge on the south bank.
The native people found around the Gillam area are known as the "Homeguard" or "Swampy" Cree, who had settled around this area prior to the railway. They lived traditional aboriginal lifestyles until the fur trade began which accommodated them to an entirely new, modernized lifestyle. The Cree came to the settlements at Mile 330, Mile 352 & Mile 237 and settle there to be around a cheaper source of supplies. They trapped for many miles around and fished the Nelson River.
When the bridge at Mile 330 was complete, the railroad continued to be built until it reached Churchill and was fully completed in 1929.
The present town site of Gillam at Mile 326 began after the railway gangs moved on from Mile 330. The Fox Lake people settled on the hill "south switch", and the Split Lake peoples settled on the north side of the tracks.
Len Gordon who arrived at Gillam in 1932 for the railways took over the general store, "Lindel's" and operated it as the "White Fox Store". It closed in 1967. The Hudson's Bay Company started a store in 1927/28, on the lot where the current Royal Canadian Legion stands. It was rumoured to be purchased for a single barrel of beer. The Hudson's Bay Company store closed in 1968, and the building was remodeled to become the present Legion Hall. The first one room school was constructed in 1927/28. However, it was burnt down and a new school was built. The first Gillam Hotel was established by Tom Allen, taken over by Pidy Striefel until it burnt down. The present hotel was constructed in 1968. The very first church that was built in Gillam was the Anglican church, presently found in the lot beside it. It was built by logs that had been floated down the Kettle River from a saw mill owned by a maintenance foreman, Lorne Bunn. Lorne lived down the tracks. The Roman Catholic Church was built in 1942, but was demolished 1967 and was rebuilt across from the Gillam Hospital. Ministers and religious teachers were brought into Gillam from the Northern Evangical Mission.
Gillam was once a migration route for Barrenland Caribou, but by 1956 the last migrating herd to travel this route passed through what is presently the school grounds. There was also an attempt on farming made by a restaurant owner, McDonald on the esker southwest of Landing Lake, in the coulee below the saddle dam. However, his attempt failed.
Around 1966, It was decided that the north held a great potential for hydroelectric power. The starting of Kettle Generating Station increased the population of Gillam to over 3,000. Gillam became a modernized "suburban" town complete with housing, shopping mall, recreational center, hospital, Nursery - Grade12 school, water and sewage treatment plants, staff houses, three churches, and an airport , and bus and train stations. Also, after the construction of Kettle was complete, Longspruce and Limestone Generator Stations were constructed. Gillam currently has a population of approximately 1,200 residents.