Quantification of landscape characteristics is important to ecosystem management planning and implementation. Key ecosystem elements, associated indicators, and their natural range of variability must be identified to establish and measure achievment of restoration goals in giant sequoia ecosystems. Giant sequoia groves have a vastly different vegetative structure today as compared to pre Euro American times (i.e., prior to 1875). This study was undertaken to inventory, compare gap size attributes, and evaluate locational features of gaps for the Converse Basin and Redwood Mountain giant sequoia groves (i.e., groves of vastly different past disturbance histories). Canopy gaps were identified on 1:12000 scale color aerial photography and transferred to georeferenced ARCVIEW files. Fire occurrence, vegetation, slope, geology, aspect, and elevation in the Redwood Mountain Grove were evaluated for their influence on mean canopy gap size. A total of 540 canopy gaps were identified in the Redwood Mountain Grove having a mean gap area of 0.22 hectares (0.55 acres) and a mean perimeter to area ratio of 0.152. A total of 672 canopy gaps were identified in Converse Basin Grove having a mean gap area of 0.32 hectares (0.79 acres) and a mean perimeter to area ratio of 0.140. Of the canopy gap characteristics compared, only canopy gap perimeter to area ratio differed significantly (alpha 0.05) between groves (p=0.0000). The majority of canopy gaps, 72% for Redwood Mountain and 68% for Converse Basin are less than 0.5 acres (0.20 ha) in size. Although dominating numerically, these smaller canopy gaps occupied only 31% of the canopy gap area in Redwood Mountain and 23% in Converse Basin. Aspect significantly influenced mean canopy gap size (p=0.032), with the larger gaps being located on southern and eastern exposures. Mean canopy gap size was significantly larger (0.10 ha) in areas subjected to fire within the last 70 years (p=0.003). Vegetation growing within gaps varied significantly (p=0.000) with mean canopy gap size. This study has quantified canopy gap occurrence and distribution for two structurally different giant sequoia groves with the results suggesting that geophysical factors influence size, frequency, and distribution of canopy gaps within giant sequoia groves.