Istrian sacral architecture during the 17th and 18th century is a special phenomenon in the corpus of national cultural heritage. During this period a large number of churches were built, which, due to their formal similarities, are classified into typical groups. Particularly noteworthy, in terms of importance for this work, are the churches of the late Palladian type and those of the so-called Pićan-Senj groups. The classicist elements of Venetian provenance are especially pronounced in them, which are manifested in the shaping and analysis of the interior of the church and the articulation of the facade. Analyzing individual examples, within such specific groups, it will be concluded that in the area of Istria, the classicist elements of architecture are often interpreted more freely, which is interpreted by the influence of builders and clients. Also, the importance of the specifics and geopolitical conditions of the Istrian peninsula that resulted in the manifestations of Karaman's concept of "border environment" prone to incorporate different stylistic influences will be emphasized.