Technique of Change Detection using LANDSAT satellite imagery helps in understanding the dynamics of landscape. This study depicts the spatio-temporal dynamics of land use/cover of Pithoragarh town area situated in Uttarakhand district of India. To quantify the changes in land use and land cover in Pithoragarh town over a period of 23 years. LANDSAT satellite imageries of two different time period i.e. LANDSAT Thematic Mapper (TM) of 1990 & LANDSAT OLI of 2013 were obtained with the help of USGS Earth Explorer. To fulfil the classification, purpose unsupervised Classification methodology has been used using the K-means technique. Study area was categorized into four different classes. i) Vegetation, ii) Agriculture, iii) Built-up, and vi) Barren land. Results of this study indicates that built-up land have been increased by 38.73% (3.55km2 ) and while vegetation, agriculture, and barren land, have decreased by -17.20% (-1.57 km2 ), 10.58% (-0.96km2 ), - 10.94% (-1.01km2 ), respectively in past 23 years. This study is being conducted first time for this study area. Thus, this paper determine application of GIScience in change detection of land use pattern.