Use:
SELECT a.AccountNo,
a.ParcelNo,
a.LocalNo,
a.PrimaryUseCode,
a.DefaultTaxDistrict,
TRIM(g.Section),
TRIM(g.Township),
TRIM(g.Range)
FROM tblAcct A
LEFT JOIN tblAcctLegalLocation g ON g.accountno = a.accountno
AND g.verstart <= '20100917999'
AND g.verend > '20100917999'
WHERE a.verstart <= '20100917999'
AND a.verend > '20100917999'
AND a.DefaultTaxDistrict="2291"
AND SUBSTR(a.AccountNo,1,1) IN ('R', 'I')
AND SUBSTR(a.ParcelNo,1,1) NOT IN ('7', '8')
AND a.AcctStatusCode IN ('A', 'T', 'E')
ORDER BY a.ParcelNo, a.LocalNo
Everything you see marked with the (+)
must be included in the OUTER join criteria. In an outer JOIN, the criteria is applied before the join.