I just received the following update on the McHenry County Prairie Trail construction and detour from the McHenry County Conservation District .
“A detour is in place and signs are posted through the Algonquin Bypass Area. (From the ramp in Algonquin you head NE on Harrison and take a left on Washington; the signs then guide you left along Route 31/Main St. back to the trail to head north.)”
I haven’t been on this trail yet this year myself but the detour would be just after you cross the Fox River heading north into Algonquin.
Just an fyi, for those of you who may not be that familiar with this trail, the McHenry County Prairie Trail is the trail that connects to the northern end of the Fox River Trail in Algonquin and continues north to Genoa City, Wisconsin.
You can actually ride these 2 trails from Oswego, Illinois to Genoa City, Wisconsin! There are a few breaks in the trail ~ like going through Aurora ~ and there is construction occasionally ~ as described above ~ but you can ride these trails all day if you want to.
I have actually ridden the entire distance of both of these trails but on multiple rides. I did do a 100 mile ride one time taking the Fox River Trail north from Geneva, Il then connecting to and riding the Prairie Trail north to Genoa City, Wisconsin then back to Geneva. Most parts of both of these trails are paved too.
Anyway, the update above is the latest info that I have on the Prairie Trail.
I took the McHenry County Prairie Trail detour through Algonquin last week and posted an update with photos (from my phone).
See the updates here > http://www.about-bicycles.com/BikeTrailPages/PrairieTrailDetour20140501.html
You can get through but it is pretty rugged.