The Montana flag displays a representation of the state seal on a field of deep blue, with gold fringe on the upper and lower borders. Above the great seal is the word "Montana" in gold Helvetica Bold font (the letters are to equal 1/10 the vertical measurement of the flag). The original banner was hand-made and carried by Montana volunteers in the Spanish-American war, but the design was not adopted as Montana's official state flag until 1904.

The state seal displays symbols of Montana's history and natural beauty. A sunrise shines over snowy mountains. Waterfalls, the Missouri River, mountains, hills, trees, and cliffs are shown behind three tools (a pick, a shovel, and a plow) which are symbols of Montana's mining and farming history. A ribbon with the state motto, Oro y Plata (Spanish for "gold and silver ") is displayed at the bottom of the seal.

Source:

About the State Flag: SOS, Montana.gov
About the State Seal: SOS, Montana.gov
Montana Facts and Figures - State Flag: MontanaKids

Links:

State Flags - 50 states List
National Flag