Dunnellon is southwest of Ocala, in Marion County, near the Withlacoochee River. Buyers who start there are often trading a shorter Ocala commute for a smaller-town setting or a lot with more outdoor room. That trade is personal. Measure the drive you would make, and look at the specific lot rather than the town slogan.
River proximity is a reason to ask about flood zones and insurance early, not a reason for this page to claim that a street does or does not flood. The flood determination belongs to the map and the insurer for that address. Septic and well systems are common enough in rural parts of the county that you should ask which utilities serve the house before you assume a city bill.
William can fold Dunnellon into a Marion County search through Homerun Realty, LLC. Compare it with Belleview and Silver Springs only after you know which errands matter. Vacant acreage without a home you plan to buy is a land-site question, not a house listing.