<TABLE> <S> <C>
<PAGE>
<ARTICLE> 5
<LEGEND>
THIS SCHEDULE CONTAINS SUMMARY FINANCIAL INFORMATION EXTRACTED FROM PLAINS
RESOURCES, INC. AND SUBSIDIARIES CONSOLIDATED BALANCE SHEET AS OF SEPTEMBER 30,
2000 AND CONSOLIDATED STATEMENT OF INCOME FOR THE NINE MONTHS ENDED SEPTEMBER
30, 2000, AND IS QUALIFIED IN ITS ENTIRETY BY REFERENCE TO SUCH FINANCIAL
STATEMENTS.
</LEGEND>
<CIK> 0000350426
<NAME> PLAINS RESOURCES, INC.
<S> <C>
<PERIOD-TYPE> 9-MOS
<FISCAL-YEAR-END> DEC-31-2000
<PERIOD-START> JAN-01-2000
<PERIOD-END> SEP-30-2000
<CASH> 9,866
<SECURITIES> 0
<RECEIVABLES> 411,539
<ALLOWANCES> 0
<INVENTORY> 29,548
<CURRENT-ASSETS> 450,953
<PP&E> 1,248,623
<DEPRECIATION> 429,874
<TOTAL-ASSETS> 1,371,881
<CURRENT-LIABILITIES> 419,230
<BONDS> 0
137,721
23,300
<COMMON> 1,814
<OTHER-SE> 35,249
<TOTAL-LIABILITY-AND-EQUITY> 1,371,881
<SALES> 2,457,018
<TOTAL-REVENUES> 2,512,484
<CGS> 2,300,375
<TOTAL-COSTS> 2,370,004
<OTHER-EXPENSES> 0
<LOSS-PROVISION> 0
<INTEREST-EXPENSE> 41,912
<INCOME-PRETAX> 61,117
<INCOME-TAX> 23,835
<INCOME-CONTINUING> 37,282
<DISCONTINUED> 0
<EXTRAORDINARY> (4,988)
<CHANGES> 0
<NET-INCOME> 32,294
<EPS-BASIC> 1.18
<EPS-DILUTED> 1.09
</TABLE>