In 1895, the first NWMP post was established in the Yukon at Forty Mile. It was named Fort Constantine after Inspector Charles Constantine. Nine buildings were erected with a stockade around the fort.
Inspector Harper visited the post at Fort Cudahy [Fort Constantine] in the summer of 1898 and recommended that if the post were to be only 4 or 5 men that the buildings be abandoned and a building be taken at Forty Mile as this is where the majority reside, there being only about 6 people living at Fort Cudahy. Inspector Scarth reports that the population of Forty Mile is 200 white men and 80 Indians. (Report of the North-West Mounted Police, 1898. Ottawa: Queen’s Printer. 1899:30, 75.)
In 1901, the Forty Mile detachment was moved across the Fortymile River as all the stores, saloons and settlers are on this side. Corporal Goodall was in charge of the detachment and he collected $599 in royalties. One corporal, 4 constables, 1 dog team and 2 canoes were at the post. (Report of the North-West Mounted Police, 1901. Sessional Papers, Volume 11. Ottawa: Queen’s Printer. 1902:9, 50, 53.)
In 1903, anyone travelling downstream in a small boat or raft had to stop at Fortymile for a search. The NWMP were trying to stop people taking gold out of the country without paying the duty. If they went past, a small detachment under canvas downstream would intercept the vessel and search it. It was Superintendent Wood's belief that it was easy for people and gold to disembark above Forty Mile and then to rejoin the boat after it had been searched. He did not have enough men to remedy the situation. On Congdon's recommendation, the police started to conduct personal searches of anyone suspected of hiding dust on their person. Kate Ryan was hired in Whitehorse to search women travellers. (Jim Wallace, Forty Mile to Bonanza: The North West Mounted Police in the Klondike Gold Rush. Calgary: Bunker to Bunker Publishing. 2000: 222.)
In 1906, the Forty Mile detachment was the port of entry for the Customs Department and a very important point as the detachment was able to keep a strict surveillance and check on all people entering and leaving the country by the lower river. The police continued to detect the parties attempting to evade the payment of the export tax on gold dust by going down the river in small boats. (Royal North-West Mounted Police Annual Report. Sessional Paper No. 28. 1906:34.)
In 1912, Forty Mile was the only detachment where a member of the force acted as an agent to the Mining Recorder, Crown Timber and Land Agent. The detachment was open all year with 1 N.C. officer and 1 constable. (Report of the North-West Mounted Police, 1912. Sessional Paper No. 28. Ottawa: Queen’s Printer. 1912:238, 242.)
The Fortymile post was shut down in 1929 when Ottawa decided to limit the outposts and use postmasters as customs collectors. By 1935 the police were again collecting customs at Fortymile and they left the town around 1938. (Rob Ingram, "Customs Offices: A Theme Study". Prepared for Heritage Branch, 1990:4.)