diff --git a/CHANGES.txt b/CHANGES.txt
index ed48d1b8f7a..000ca47e774 100644
--- a/CHANGES.txt
+++ b/CHANGES.txt
@@ -195,6 +195,12 @@ Changes in runtime behavior
     basis. There is currently no way provided to rebase the docids in the Scorer to 
     the top level IndexReader.  (Mark Miller, Mike McCandless)
 
+14. LUCENE-1846: DateTools now uses the US locale to format the numbers in its
+    date/time strings instead of the default locale. For most locales there will
+    be no change in the index format, as DateFormatSymbols is using ASCII digits.
+    The usage of the US locale is important to guarantee correct ordering of
+    generated terms.  (Uwe Schindler)
+
 API Changes
 
 1. LUCENE-1419: Add expert API to set custom indexing chain. This API is 
diff --git a/contrib/analyzers/common/src/test/org/apache/lucene/analysis/sinks/DateRecognizerSinkTokenizerTest.java b/contrib/analyzers/common/src/test/org/apache/lucene/analysis/sinks/DateRecognizerSinkTokenizerTest.java
index cbb6990b820..baad73dddd5 100644
--- a/contrib/analyzers/common/src/test/org/apache/lucene/analysis/sinks/DateRecognizerSinkTokenizerTest.java
+++ b/contrib/analyzers/common/src/test/org/apache/lucene/analysis/sinks/DateRecognizerSinkTokenizerTest.java
@@ -19,6 +19,7 @@ package org.apache.lucene.analysis.sinks;
 import java.io.IOException;
 import java.io.StringReader;
 import java.text.SimpleDateFormat;
+import java.util.Locale;
 
 import junit.framework.TestCase;
 
@@ -41,7 +42,7 @@ public class DateRecognizerSinkTokenizerTest extends TestCase {
   }
 
   public void test() throws IOException {
-    DateRecognizerSinkFilter sinkFilter = new DateRecognizerSinkFilter(new SimpleDateFormat("MM/dd/yyyy"));
+    DateRecognizerSinkFilter sinkFilter = new DateRecognizerSinkFilter(new SimpleDateFormat("MM/dd/yyyy", Locale.US));
     String test = "The quick red fox jumped over the lazy brown dogs on 7/11/2006  The dogs finally reacted on 7/12/2006";
     TeeSinkTokenFilter tee = new TeeSinkTokenFilter(new WhitespaceTokenizer(new StringReader(test)));
     SinkTokenStream sink = tee.newSinkTokenStream(sinkFilter);
diff --git a/src/java/org/apache/lucene/document/DateTools.java b/src/java/org/apache/lucene/document/DateTools.java
index b4db10aa20f..e45ab052fef 100644
--- a/src/java/org/apache/lucene/document/DateTools.java
+++ b/src/java/org/apache/lucene/document/DateTools.java
@@ -22,6 +22,7 @@ import java.text.SimpleDateFormat;
 import java.util.Calendar;
 import java.util.Date;
 import java.util.TimeZone;
+import java.util.Locale;
 import org.apache.lucene.search.NumericRangeQuery; // for javadocs
 import org.apache.lucene.util.NumericUtils; // for javadocs
 
@@ -52,13 +53,13 @@ public class DateTools {
   
   private final static TimeZone GMT = TimeZone.getTimeZone("GMT");
 
-  private static final SimpleDateFormat YEAR_FORMAT = new SimpleDateFormat("yyyy");
-  private static final SimpleDateFormat MONTH_FORMAT = new SimpleDateFormat("yyyyMM");
-  private static final SimpleDateFormat DAY_FORMAT = new SimpleDateFormat("yyyyMMdd");
-  private static final SimpleDateFormat HOUR_FORMAT = new SimpleDateFormat("yyyyMMddHH");
-  private static final SimpleDateFormat MINUTE_FORMAT = new SimpleDateFormat("yyyyMMddHHmm");
-  private static final SimpleDateFormat SECOND_FORMAT = new SimpleDateFormat("yyyyMMddHHmmss");
-  private static final SimpleDateFormat MILLISECOND_FORMAT = new SimpleDateFormat("yyyyMMddHHmmssSSS");
+  private static final SimpleDateFormat YEAR_FORMAT = new SimpleDateFormat("yyyy", Locale.US);
+  private static final SimpleDateFormat MONTH_FORMAT = new SimpleDateFormat("yyyyMM", Locale.US);
+  private static final SimpleDateFormat DAY_FORMAT = new SimpleDateFormat("yyyyMMdd", Locale.US);
+  private static final SimpleDateFormat HOUR_FORMAT = new SimpleDateFormat("yyyyMMddHH", Locale.US);
+  private static final SimpleDateFormat MINUTE_FORMAT = new SimpleDateFormat("yyyyMMddHHmm", Locale.US);
+  private static final SimpleDateFormat SECOND_FORMAT = new SimpleDateFormat("yyyyMMddHHmmss", Locale.US);
+  private static final SimpleDateFormat MILLISECOND_FORMAT = new SimpleDateFormat("yyyyMMddHHmmssSSS", Locale.US);
   static {
     // times need to be normalized so the value doesn't depend on the 
     // location the index is created/used:
diff --git a/src/test/org/apache/lucene/document/TestDateTools.java b/src/test/org/apache/lucene/document/TestDateTools.java
index e27d2a5217b..afaf75e9860 100644
--- a/src/test/org/apache/lucene/document/TestDateTools.java
+++ b/src/test/org/apache/lucene/document/TestDateTools.java
@@ -5,6 +5,7 @@ import java.text.SimpleDateFormat;
 import java.util.Calendar;
 import java.util.Date;
 import java.util.TimeZone;
+import java.util.Locale;
 
 import org.apache.lucene.util.LuceneTestCase;
 
@@ -172,7 +173,7 @@ public class TestDateTools extends LuceneTestCase {
   }
 
   private String isoFormat(Date date) {
-    SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss:SSS");
+    SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss:SSS", Locale.US);
     sdf.setTimeZone(TimeZone.getTimeZone("GMT"));
     return sdf.format(date);
   }