The Census Bureau estimates 28,592 in July 2011.
595000
157 miles
It is 637.69 miles to Helena, Missouri and 860.95 miles to Helena, Montana from Colorado Springs. It is therefore 1,498.64 miles from Helena, Missouri to Helena Montana via Colorado Springs, Colorado and the mileage direct from Helena, Missouri to Helena, Montana is only 1,219.79 miles by skipping Colorado.
Mapquest says it is 113.14 miles.
37000
The driving distance from Helena, Montana to Bozeman, Montana is 97 miles via US-12 East per MapQuest. The driving time per MapQuest is 1 hour and 33 minutes.
like 800 something
It depends on which Helena you're in--there are many places in the United States (and presumably elsewhere) named Helena. The most famous is the capital of Montana, and it's probably the largest, too.
It is 1,740 miles according to Google Maps.
It is 1,816 miles according to Google Maps.
Assuming that the question is referring to Helena, Montana . . . If you travel the short way from Helena to Ulaanbaatar, you cover 141 degrees of longitude.
Google Maps estimates the driving time as 3 hours and 28 minutes.