彭世洛是泰国北部偏南区的一个重要的历史性都市，彭世洛府首府，接近老挝边境。彭世洛是泰国古都之一，于600多年前建城。此地因为是纳黎萱王诞生地而著称，16世纪时他让彭世洛脱离缅甸的统治，继位者是他的兄弟Ekathosarot王(Sanpetn三世)。

彭世洛位于泰国北部和中部交界要冲，长久以来因为同时具备政治与战略重要性，过去曾发生过数次战争。阿瑜陀耶(Ayutthaya)的若玛特罗卡纳王期间25年，将泰国首都设于此地。

整个城市沿着楠河岸。11世纪小桂河改道前，彭洛世是高棉前哨，名为Song Kwae。

Phitsanulok (Thai:พิษณุโลก, pronounced [pʰít.sa.nú.lôːk]) is an important, historic city in lower northern Thailand and is the capital of Phitsanulok Province, which stretches all the way to the Laotian border. Phitsanulok is one of the oldest cities in Thailand, founded over 600 years ago. It is probably best known as the birthplace of King Naresuan, who freed the country from Burmese domination in the late 16th century, and that of his brother and successor King Ekathosarot (Sanphet III). As the crossroad between the northern and central regions of the country, it has long been important both for political and strategic reasons, and was fought over many times in centuries past. Phitsanulok was the capital of Thailand for 25 years during the reign of King Boromma Trailokanat of Ayutthaya. On the banks of the Nan River, the city was originally a small Khmer outpost known as Song Kwae, before the Khwae Noi River changed its course in the 11th century CE. Phitsanulok was also a provincial center of the Angkorian Empire during the Angkorian period. Phitsanulok is home to Naresuan University and Pibulsongkram Rajabhat University, as well as to a major Royal Thai Army base.