First, you need to be told, this is a very bad area. I would not leave a car in any unsecured area.
There is a parking structure for Union Station with over night parking. However, it has terrible reviews with a 2.9 rating. There's no security after 10pm and it's a awful area. Many people have had their vehicles broken into & damaged. Google "Info on Union Station in Portland, Oregon" & you'll get their website.
Yes there is overnight parking but I suggest you either go and ask questions to get straight answers or check the website for frequently asked questions and answers plus look for the 1-800 number to call. There are places you can leave your car under a carport, but. you may want to look into this matter a bit further
I know you can park at greyhound across the street but im not sure of the price.
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