Hrvatsko zagorje (ili kraće Zagorje) jedna je od hrvatskih regija prepoznatljiva naziva i obilježja (brežuljkast kraj, gusta naseljenost, bogato spomeničko naslijeđe). U razdoblju od 2014. do 2017. u Leksikografskome je zavodu izrađena regionalna enciklopedija posvećena Hrvatskome zagorju. Jedno od temeljnih pitanja za uredništvo Enciklopedije Hrvatskoga zagorja bilo je odrediti područje koje regija obuhvaća. Polazeći od općega enciklopedijskog načela sveobuhvatnosti, uredništvo Enciklopedije odlučilo je prihvatiti širu definiciju područja prema kojoj ono obuhvaća Krapinsko-zagorsku županiju u cjelini te dijelove Varaždinske i Zagrebačke županije. U članku se donosi pregled različitih definicija zagorskoga područja u stručnoj literaturi, na temelju kojih je uredništvo Enciklopedije i zauzelo svoje stajalište. Također se donose i temeljne informacije o podrijetlu horonima Hrvatsko zagorje.Hrvatsko Zagorje (or simply Zagorje) is a region in northwestern Croatia with a widely recognizable name and distinctive characteristics (hilly and densely populated area, rich cultural inheritance). Between 2014 and 2017 The Miroslav Krleža Institute of Lexicography produced an encyclopedia devoted exclusively to the Zagorje region. One of the essential conceptional issues for its editors was to determine the area of the region, and consequently define the area which is to be described by the encyclopedia. Taking into account that encyclopedias generally favour a holistic approach, which includes all relevant facts, the editors decided to accept and apply a wider definition of the region elaborated in many books and articles. Within the encyclopedia Zagorje was defined in such a way to include the Krapina-Zagorje (which is the core-region) County in total, as well as neighbouring parts of the Varaždin and Zagreb counties. This article reviews different territorial definitions of Zagorje which served as a basis for the standpoint taken by the editors of the encyclopedia. The article also provides basic information on the etymology of the toponym Hrvatsko Zagorje