This is the connection that binds Lincoln, both physically and metaphorically. Any given morning on the weekend, or evenings during the bulk of the year, you can find folks running, biking, walking, commuting. Outside of the soft trails at the edge of town, this might be the best training trail in Lincoln. Very few traffic crossings, marked miles, shade, even a dirt singletrack that has been worn in next to it.
Following an old rail graded path (like most trails in Lincoln), it runs from about 22nd and O streets all the way to the Cooper YMCA in south Lincoln. It is possible to connect to about any trail in Lincoln via Rock Island. It is by far my favorite place to train, mostly due to convenience. But it is also THE place to run in Lincoln. Granted, it can get crowded on a nice evening, but that is just company to keep you motivated.