British Columbia introduced its flag in 1960, on June 14, and was first flown on ships of the BC Ferries line. The flag itself features a Union Jack over the top half, defaced by the King Edward Crown. The bottom half features 4 white and 3 blue wavy lines, overlaid by a setting sun.
The Union Jack is placed over the top to represent the old British axiom "Sun never sets on the British Empire." And the crown represents the Canadian Royal family. The white and blue lines represents British Columbia's position as between the Pacific Ocean, and the Rocky mountains.
The setting sun represents the fact that British Columbia is Canada's most westerly province.