X0202 4 2006-04-10 0 0000075129 OTTER TAIL CORP OTTR 0001180965 PARTAIN NATHAN I 215 S CASCADE ST FERGUS FALLS MN 56537-2801 1 0 0 0 Common Stock 2006-04-10 4 A 0 2200 28.235 A 4100 D Shares of Common Stock acquired under the Corporation's Stock Incentive Plan, which is a grant of Restricted Stock. The 2,200 shares granted 4/10/06 have a grant price of $28.235 and vest at 25% yearly beginning 4/8/07. See below for other holdings: 1. Direct holding of 1,000 shares held in "street name" with Merrill Lynch. 2. Direct holding of 2,193.1057 shares held in the Dividend Reinvestment Plan. 3. Direct holding of 1,200 shares which no longer carries the restriction. 4. Indirect holding of 1,600 shares held by an IRA. 5. 2,000 stock options with expiration date of 4/9/2010. 6. 2,000 stock options with expiration date of 4/8/2011. /s/ Nathan I Partain by Debra J Lill -POA 2006-04-12