Tysons towers in Vienna, but unsure what availability is. Established for low income seniors.

Not Montgomery County, but close to Maryland -- Friendship Terrace, near the Tenleytown metro in DC. It's for low-income seniors who are still pretty independent. They serve dinner in a dining hall, which you have to sign up for (so monthly charge is housing plus dinner charges), and lunch, which you may sign up for. Shuttle buses to various locations weekly, some activities, but no internal resources if you need memory or nursing care.

Would you consider Arlington? Hunter's Park in Cherrydale is a hidden gem.

70s is young. Do they have health issues? Why it just downsize to a condo near some activities restaurants and stores.

Goodwin House is very nice, but hardly for low income seniors.

Goodwin house is wonderful. It is the Ritz Carlton for senior living. They are in Arlington and Falls Church.

In Arlington, there is Culpepper Gardens.

For Fairfax County. You can start with "http://www.fairfaxcounty.gov/rha/seniorhousing/shs-2015.pdf"
The wait is about 2.5 yrs to 5 yrs. They are for senior low income housing but few are very nice.
I did it for my parents 2 yrs ago.
Good luck.

I trying to find housing for my senior parents in their 70s. They can still do things on their own. I am wondering if anyone can tell me where to look for senior housing in 1) Montgomery County, 2)Fairfax County.
Are there any low income housings? Can I rent a senior housing for them?
I am at lost. How and where do I begin?