The Ohio to Erie Trail (OTET) is the easiest long-distance trail to access from Portage County.  It is just a quick hop from the Portage Hike and Bike Trail to Summit County's Freedom Trail.  See the map on the Connecting to the Towpath Trail page to learn how to bridge a short gap between the incomplete Freedom Trail and the Towpath Trail (also part of the Ohio to Erie Trail).

If you are determined to start at OTET Mile Zero in Cleveland, you may want to be dropped off there.  However you can reach it by bike via the Summit Hike and Bike Trail and Towpath Trail.  You'll be retracing your steps (15-30 miles worth from Portage County) when you head south.

All the resources you may need to complete this trip can be found at the official website;
www.ohiotoerietrail.org/  The first map below is from this site (captured in 2020) and provides a good overview of the route.  Detours and alerts are updated frequently on the website, so ignore the warning symbols on the map provided here.  The website will list a primary route through Columbus that takes you near or through bits of downtown.  The second map below provides a tested northern route that avoids downtown and sticks entirely to trails, bike lanes and quieter neighborhood roads.

There are a number of road sections along this Trail, including travel through the city of Columbus.  The Wayne County gap (Dalton to Fredericksburg) is the hilliest, with a least one steep beast southbound that may require walking.  As of 2022, about 11% of the trail is on rural roads and city streets.  A short rural road section in Holmes County will be replaced with trail with construction starting in 2023.

Not Interested in Cleveland?  Ride to Ashtabula Instead
Those interested in a slightly longer trip (and a more complete diagonal across the state) may wish to start or end at Lake Erie in Ashtabula.  You can find this route on the "Ohio to Erie Trail Alternate" page. 
 

Alternate Route Through Columbus from Westerville to Georgesville
The map below details a route I used in August 2024 to cut across the north side of Columbus.  I was traveling southbound (actually SW) from Westerville.  The map ends at Georgesville where there is an interuption in the trail that requires a few blocks of road travel.   Note that the OTET site may list an official northern route through Columbus that is somewhat different.

Heading west (southbound), various contiguous trails run along the south side of Polaris Parkway, eventually becoming the Alum Creek Trail, and heading south away from the parkway.  A spur trail takes you to Sharon Woods, where you need to use the car road when heading in this direction as the bike trail is one-way in the opposite direction.  Exiting Sharon Woods you ride in a bike lane along busy Schrock Rd for about 2.7 miles. Finally, you navigate through some quiet neighborhood streets to reach the Olentangy Trail.  This leads you to the Lower Scioto Greenway, part of the official OTET route.