According to the U.S. Census Bureau, the census-designated place (CDP) has a total area of 14.8 square miles (38 km2), all land.

Hyder has a fairly typical Southeastern Alaskan oceanic climate (Köppen Cfb, borderline Dfb), although using the 0 °C or 32 °F coldest-month isotherm it has an extremely wet and ocean-moderated version of a warm-summer humid continental climate (Köppen Dfb) similar to that of Haines although substantially wetter.

Stewart, British Columbia, immediately borders Hyder and is accessible by road via International Street.

Outside of the town site, NFD-88 heads in a northerly direction winding through the Tongass National Forest, and enters the outer extent of Stewart's municipal limits continuing as Granduc Road.

[5] Electricity is maintained by a subsidiary of BC Hydro, the Tongass Power and Light Company as part of a long-term contract[18] with the town.

[20] The Nisga'a, who lived around the Nass River, called the head of Portland Canal "Skam-A-Kounst," meaning safe place, probably because it served them as a retreat from the harassment of the Haidas on the coast.

[23] In 1898, gold and silver lodes were discovered in the region, mainly on the Canadian side, in the upper Salmon River basin.

Hyder's boom years were the 1920s, when the Riverside Mine on the U.S. side extracted gold, silver, copper, lead, zinc, and tungsten.

[24] Westmin Resources Ltd operated a gold and silver mine on the Canadian side in Premier, British Columbia, but is not currently active.

[20] It is the location of the annual Hyder Seek gathering of long-distance motorcyclists who travel from all over North America each Memorial Day weekend.

It became popular with long-distance motorcycle riders in 1998, when author Ron Ayres set a record of riding to the contiguous 48 states in six days.

[26][27][28][29][30][31] Hyder was the starting point of the 2014 coast-to-coast Scooter Cannonball Run, which ended in New Orleans, Louisiana.

A local tradition is known as being "Hyderized", with two of the town's bars issuing certificates to patrons who consume a shot of 151 proof (75.5% alcohol) Everclear.

[38] The sign was erected in 2015 as a protest after the Canadian administration announced plans to close the border control at night.