Using mean basin slope and watershed area to lake surface area ratios, 58 Iowa lakes were classified into four distinct groups. Physical factors that can be altered very little once a lake is constructed may drastically affect sport fishing and the cost of maintaining quality fishing. Mean basin slope ([Sbar]) and watershed to lake area ratios (WA) can be determined prior to lake construction, and should ultimately influence lake site and construction plans. The exact relationship between the physical parameters, lake quality, and quality of the fishery in Iowa is unknown. Understanding these relationships will assist in developing fish management programs for existing lakes and describing the fisheries potential of proposed lakes. The lake groups formed used the following criteria: Group A, WA 0/–30:1 and [Sbar] greater than 8 percent; Group B, WA 30/–80:1 and [Sbar] greater than 4 percent; Group C, WA 0/–30:1 and [Sbar] below 8 percent; Group D, WA greater than 40:1 and [Sbar] below 8 percent. A lake with WA greater than 80:1 or with [Sbar] below 2 percent would also be classified as Group D. Angler acceptable standing stock was composed of bluegill,Lepomis macrochirus, and redear sunfish,Lepomis microlophus, TL 152 mm (6 in.) or larger; crappie,Pomoxis sp., TL 203 mm (8 in.) or larger, largemouth bass,Micropterus salmoides, TL 254 mm (10 in.) or larger, channel catfish,Ictalurus punctatus, TL 305 mm (12 in.) or larger, and black bullhead,Ictalurus melas, TL 203 mm (8 in.) or larger. Mean standing of fish varied among lake groups, ranging from 652 kg/ha (583 lbs/acre) to 808 g/ha (722 lbs/acre). Mean standing stock acceptable to anglers was 309 kg/ha (276 lbs/acre) in Group A lakes, 464 kg/ha (415 lbs/acre) in Group B lakes, 478 kg/ha (427 lbs/acre) in Group C lakes, and 132 kg/ha (118 lbs/acre) in Group D lakes. Statistical analysis revealed that mean standing stock of angler acceptable fish was significantly greater in Groups A and B lakes than in Group D. Group B lakes produced a significantly higher mean standing stock of angler acceptable fish than Group A. These data suggest that lakes with basin and watershed characteristics similar to those in Group B produce maximum angler acceptable fish standing stocks.