It has an asphalt surface and begins at Deer Grove Forest Preserve (Dundee Road Route 68 and Quentin Road). There is also a 3.9 mile connector trail and loop through Deer Grove East Forest Preserve. Its southern terminus is at Maple Park at Winston Drive and Anderson Drive, although I always continue south on Winston, crossing Palatine Road at the traffic signal, and then turn left onto Frontage Road and take that around to Twin Lakes Recreation Area, which has a nice loop trail, a concession stand, and washrooms.
The section following the old railway line just south of Dundee Road has become a nicely shaded, tree-lined route.
The trail then cuts through the Palatine Hills Golf Course, passes townhomes...
...crosses Smith Street, passes Hamilton Reservoir, turns into a lovely wood lot, goes past the library and under Hicks Road via an underpass, and then you bike east under the power towers for a while before turning south again along Salt Creek until the trail ends at Maple Park. I then continue another mile or so south to Twin Lakes Recreation Area where there is a nice loop trail, restrooms, snack bar, and water.
Below is Twin Lakes which offers picnic areas, sand volleyball, boat rentals, a nine hole golf course, and a driving range. Although the Palatine Trail per se is only about 5 miles long, by continuing to Twin Lakes and also biking the loop in Deer Grove Forest Preserve, you get a nice 18 mile ride.
Other connectors (sometimes streets) take you to other sections of Palatine's bike trails, including to and around Harper College and then north on Algonquin Road to Route 59.
Here's a map of the trails and streets you can bike in and around Palatine.