本文透過清政府在乾隆26年（1761）所構築的「土牛溝」，試圖探討台灣內山開墾史的區域範圍，在不同時期隨著清帝國對「版圖」觀念的改變，以及內、外在因素的影響所產生的變化。另一方面，則經由這種統治權的逐步擴張，來瞭解漢移民在版圖界外的族群互動過程，從區域取向的角度，解析客家人在台灣北部地區的族群關係。由於桃園、新竹、苗栗三縣，是台灣北部客家人的優勢區；因此，台灣北部地區的內山開墾史，客家人佔有相當重要的地位；不但從中主導了墾務的發展，改變了本地區的人口結構，也為當地的族群關係，留下深遠的影響。所以筆者將本文的討論範圍，界定在漢民開墾較晚而族群互動最為頻繁的桃、竹、苗內山地區。

This paper looks at the Tunio Ditch(Tuniu Ditch), constructed by the Ching(Qing) government in 1761 to delimit the boundary between the Han and the indigenous people, as a way of examining the continual boundary changes within Taiwan's Ne San(Nei Shan) frontier history, and how they coincided with shifts in how the Ching viewed its own domain and other internal and external factors. At the same time, the paper also examines the expansion of Ching territory as a way of understanding the interactions between Han pioneers and other tribes outside of Ching territory, and further analyzes the relationships between the Hakka and other ethnic groups in Northern Taiwan. The Hakka have been a dominant ethnic group in Taoyen (Taoyuan), Sinchu (Hsinchu) and Miaoli counties in Northern Taiwan and have played an important role in its Ne San frontier history as a result, not only directing frontier development and changing the population composition but also influencing relations between all ethnic groups. Hence the Taoyen-Sinchu- Miaoli region, which has been characterized by a high level of interaction between ethnic groups, was chosen as the scope of the paper, despite its late development by the Han.