1. Ranthambore NP (RTR): One of the most famous tigers hail from this park, many documented in Nat Geo / Animal Planet etc. Due to dry deciduous terrain i.e. scanty vegetation tiger spotting is relatively easier at RTR. The park is closed for the monsoons and opens on 1st oct. However bookings need to be at least 3-4 months in advance as there are limited permits. Main fauna is tiger, leopard, jackals,
Pros: If you wish to maximize your chances of tiger spotting and do not care much for other wildlife / landscapes. High tiger density, famous tigers
Cons: Need to stay outside the jungle in a resort, bookings are much in advance (at least 3 months)
2. Jim Corbett NP: If you wish to get the true feel of a jungle, Jim Corbett with evergreen Sal forest is the place. Known for magnificent elephant herds on the backdrop of Kumaon ranges it is a jungle experience and not just tigers. The forest is very dense making tiger spotting probability lower than RTR (though the number of tigers are more, the area is also more). Park is open from 15th Nov to 30th June. You need to book 1.5 months in advance with a booking agency ideally, again here also permits are limited. It would be a good idea to book the Dhikala Forest Rest House located in the heart of the jungle with breathtaking view of the grasslands. Lovely landscapes along the Ramganga river
Pros: Beautiful landscapes, great for birding, Elephants and overall jungle feel
Cons: Relatively low tiger density
Both these places are a 6 hour drive from Delhi