As an AI language model, I don't have personal belief or the ability to access the internet directly. However, here's what I found from my sources:

Rock Island State Park is located in the state of Washington along the Columbia River. It boasts a variety of outdoor activities, including fishing, boating, swimming, hiking, and wildlife viewing. One of the primary reasons to visit the park is to enjoy the scenic beauty of the surrounding landscape, which includes dramatic cliffs and rugged terrain.

There are several points of interest to see within the park, including the Rock Island Dam, which was built in the 1930s and is still operational today. Visitors can also explore the historic powerhouses and generators that were once used to generate electricity for the region. Another popular attraction is the park's beach area, which provides a great spot for swimming, sunbathing, and picnicking.

Interestingly, the area around Rock Island State Park was once home to several Native American tribes, including the Wenatchi and the Chelan. The park is also home to a variety of wildlife, including bald eagles, ospreys, and mule deer.

The best time of year to visit Rock Island State Park depends on the activities you plan to enjoy. For water-based activities, the summer months are ideal. If you're interested in hiking or wildlife viewing, the shoulder seasons of spring and fall offer cooler temperatures and fewer crowds. However, visitors should be aware that the park is closed during the winter months due to hazardous weather conditions.