You can park right at the trail head/passage off 135th, there are limited spaces but usually never full. There is also tons of overflow parking at Isle a la Cache Museum, but you have to ride a min or two down to the Passage and cross 135th.
The trail is (I didn't know this either) the Centennial Trail heading north towards Willow Springs; is actually the I&M from Citgo heading south towards Lockport.
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