No, this is NOT the Serpent Mound in Ohio, that is here. This is a recent one from Discovery Park in Seattle at the Daybreak Star Indian Cultural Center. There isn’t that much information from the web, that I could find about it. We found it by accident. We saw a sign that said reflecting pools and serpent mound with an arrow. We went looking for it. Then we saw the pools and we were kind of up high. I read it as “spiral mound” which didn’t make sense until Frank said, “Serpent Mound” which meant we were at the eye? I’m not positive but it was obviously a raised mound that serpentined through the woods. It was super cool on a rainy day. I loved that it was kind of not kept up too…We had to really look for it. I think you’ll need to make the pics bigger to see the “eye” of the snake.
Follow up 5/21/13:
Lisa Pekal let me know on the Facebook page that there is a map on the Discovery Park website that shows the mound! We were indeed at the “eye” of the serpent. I like that place even more now. Here is a link and it’s on page 13. Discovery Park Map The rest of the paperwork is pretty cool too by the way.
MK Barr Journal 
I bumped into this serpent mound as well and asked a ranger if it was built by the Indians or someone long ago. He seemed to get nervous and told me it was a dike made around the same time as the Indian Center to keep the pond from overflowing in the rain.
What is odd though is this “dike” isn’t protecting any buildings, just empty forest and the pond has a stream flowing out of it already for drainage. Then I found a map of the park in the Center and was quite surprised that this serpent mound looks almost IDENTICAL to the one in Ohio.
Maybe I watch too much History Channel but could there be a connection here? It does look like it was built a long time ago… Also there is a circular field nearby with wooden poles that is very similar to a place called Woodhenge in Illinois that has large pyramid like mounds. Much of America’s ancient history is not put in our textbooks, that much I know is true.
Everyone should go check this place out it’s pretty cool… but also a bit creepy.
There is a map of the location for building it from when the center was built but I wouldn’t be surprised if it was there before the center got there and they incorporated the retention pond into it. I’m familiar with the woodhenge since I went to Southern Illinois University. There is so much we don’t know but I’m glad you found it too! I love little secret places like that.