Take the A1 Autoroute du Nord (Paris - Lille motorway) - northwards from Paris, take the Chantilly exit, southwards from Lille, take the Survilliers exit. Alternatively, drivers can take the RN 16 or RN 17 trunk roads. Chantilly is usually less than one hour's drive from Paris (depending on traffic).
To access the chateau from Chantilly station, you can take a taxi from the station (€6), or catch the Cariane bus for Senlis (free in Chantilly).
To walk from from the terminal (at the head of the SNCF lines), get off at the "Chantilly, Eglise Notre Dame" stop and walk to the Chateau from the terminal, around 35 minutes.