Little black spiders
Ravalli County Montana
Thank you for submitting these similar questions from both Oregon and Montana.
In both cases, there are hundreds of spiders that are commonly found in the areas/sites that you describe. In order to identify them without any photos is impossible and even with photos it is difficult; the only way to be certain with identification is to collect samples and submit them to your local county Extension Office. It also may not be necessary to identify the spiders in either case since they do not appear to be spiders that are harmful to humans.
April, May, and June are typically the months where the most species of spiders in the greatest numbers are active. September and October are also "high" sightings months, mostly when spiders are moving into homes, shops, or woodpiles and people come across them.
Other than perhaps "startling you" or "grossing you out", it does not appear that these spiders are causing any harm or reason for concern. Spiders are a very important part of a healthy environment as they prey on many garden and field pests and are, in turn, prey for many birds and other insects.
There are resources available online to help with information about spider myths and identification but, once again, identification should be done by a specialist that is probably housed at your state Department of Agriculture or land-grant University. The local county Extension Office is a great, first stop to inquire about spider identification and the steps necessary to submit a sample.
Below is a resource for spider information in Oregon:
The aforementioned publications are also relevant to Montana in most cases but just in case, here is one from Montana State University:
I hope some of these resources are helpful or at least give you an option for addressing the spiders in both of your locations. Please feel free to reach out us again if there are other questions we can answer.