Xīnběi 新北 (generally known as New Taipei in English and formerly Taipei County) is an administrative division of Taiwan 台灣 surrounding Taipei 台北. Technically it is the most populous city in Taiwan, but that's only because it encompasses so much of Taipei's urban sprawl. There isn't any sort of unified identity to New Taipei; it's merely an administrative contrivance.
That being said, New Taipei is home to a vast wealth of historic and natural sights within easy reach of the capital. The attractions are far too numerous to list and start with historic Tamsui 淡水, the hot springs of Wūlái 烏來, the mountainside mining towns of Ruìfāng 瑞芳, Fulong Beach and the Old Caoling Tunnel in Gòngliáo 貢寮, Yeliu Geopark and the UFO village in Wànlǐ 萬里, the old streets of Sānxiá 三峽, Shēnkēng 深坑, and even Xinzhuang, the tea plantations of Pinglin, the green algal reefs of Shímén 石門, the brick kilns of Línkǒu 林口, the pottery shops of Yīnggē 鶯歌, and the entire Píngxī 平溪 railway corridor, among others.