How to advertise the grad course that you teach? I accepted an offer to teach a graduate course at the university, as an adjunct professor. This program has a minimum threshold for number of students signed up. In other words if not enough students signed up by the deadline, they won't offer it. 

I wonder how do you advertise the courses that you teach? I think the subject and content will be very interesting to many students, so the question is how to disseminate the information about it to potential students outside the graduate program that it is part of?

It's a national university in USA, ranked in top 100, not top 20 or Ivy league type. I believe that this course will be available for students of a regional consortium of universities to which this uni belongs. The course is elective, and a part of a small Masters level program, but will be listed in the catalog and should be available to students outside the program. The course is a STEM subject in STEM certified program, so it should be compatible with similar programs
First, make up an attractive one-page flyer that details what your course is about and when it's offered, and that it's STEM certified (sounds important, but I've never heard of it).

Then, contact departments at your university and at others in the consortium that may be interested in your course and ask if they would send out your flyer advertising your course to their graduate departmental mailing list. 

You might also note there needs to be a minimum enrollment (encourage people on the fence to sign up).

Where I'm at, this would usually be an advisor's job, or maybe a program coordinator, but if you know a sympathetic professor in the department you're contacting, they could also reach out to whoever manages the mailing list.