56,969 (1930 POPULATION RANK #1)
48,422 (1950 POPULATION RANK #3)
35,267 (2020 POPULATION RANK #8)

Montana standard license plates carry a county number generally based on rank said to have been established in 1933, either by the number of plates sold in 1932, or from the 1930 federal census (or some combination thereof). The first registration year to implement the new system was 1934.

At the time the system was established, Silver Bow County ranked #1 in population. In the mid 1950's, the county would have ranked third behind Yellowstone and Cascade. As of 2022, it would rank 8th. Recently the citizens approved a city-county form of government (Butte-Silver Bow). Also now with a city-county consolidated government is Anaconda-Deer Lodge.

While there was a slight population increase noted between 2010 and 2020, Silver Bow has continued to generally lose ranking over the decades to faster growing counties. In 2020, there were 11,486 pickup trucks, 9,641 passenger cars, and 9,545 SUV's registered in Butte-Silver Bow County.

There are 56 counties in Montana, and while some have maintained their relative rank over the years, others have not. And there were discrepencies in the original system. For instance, Lincoln County, which received #56 in 1934, would rank 10th today. Powder River County should not have been ranked as #9 based upon its 1930 population. Other oddities are Park County, #49 and Phillips County (#11).

Treasure County, which was assigned #33 in the system, was actually 55th (as well as today). The smallest population county today is Petroleum (2020 population 437 and 1930 population 1,025). Today Montana has three counties with populations of less than 1,000. There are eight more with populations between 1,000-2,000.

Looking at the overall ranking, there are a few county numbers that correspond to the 1930 census, but most do not. Evidently there were other factors in the numbering that have been lost to history. One theory is that the 1932 registration figures were used, numbers that were starting to reflect decling rural populations resulting from the Great Depression.

Montana's statewide population in 1930 was recorded at 539,000, and estimated at 636,000 in 1955. According to the 2020 census, the state has now barely cracked the one million mark. In 1955 the state had roughly one pair of license plates issued per three of its citizens. Today the ratio is closer to 1:1, as there are about as many pairs of license plates issued each year now as their are people.