diff --git a/agate/aggregations/__init__.py b/agate/aggregations/__init__.py
index e4f40cc..cf82a30 100644
--- a/agate/aggregations/__init__.py
+++ b/agate/aggregations/__init__.py
@@ -21,6 +21,7 @@ from agate.aggregations.all import All  # noqa
 from agate.aggregations.any import Any  # noqa
 from agate.aggregations.count import Count  # noqa
 from agate.aggregations.deciles import Deciles  # noqa
+from agate.aggregations.first import First  # noqa
 from agate.aggregations.has_nulls import HasNulls  # noqa
 from agate.aggregations.iqr import IQR  # noqa
 from agate.aggregations.mad import MAD  # noqa
diff --git a/agate/aggregations/first.py b/agate/aggregations/first.py
new file mode 100644
index 0000000..37e1695
--- /dev/null
+++ b/agate/aggregations/first.py
@@ -0,0 +1,42 @@
+#!/usr/bin/env python
+
+from agate.aggregations.base import Aggregation
+from agate.data_types import Boolean
+
+
+class First(Aggregation):
+    """
+    Returns the first value that passes a test.
+
+    If the test is omitted, the aggregation will return the first value in the column.
+
+    If no values pass the test, the aggregation will raise an exception.
+
+    :param column_name:
+        The name of the column to check.
+    :param test:
+        A function that takes a value and returns `True` or `False`. Test may be
+        omitted when checking :class:`.Boolean` data.
+    """
+    def __init__(self, column_name, test=None):
+        self._column_name = column_name
+        self._test = test
+
+    def get_aggregate_data_type(self, table):
+        return table.columns[self._column_name].data_type
+
+    def validate(self, table):
+        column = table.columns[self._column_name]
+        data = column.values()
+
+        if self._test is not None and len([d for d in data if self._test(d)]) == 0:
+            raise ValueError('No values pass the given test.')
+
+    def run(self, table):
+        column = table.columns[self._column_name]
+        data = column.values()
+
+        if self._test is None:
+            return data[0]
+
+        return next((d for d in data if self._test(d)))

agate.First aggregation
I end up doing this all the time:

```
def pick_first(c):
    return c[0]

agate.Summary('Serial_Num', agate.Text(), pick_first)
```
diff --git a/tests/test_aggregations.py b/tests/test_aggregations.py
index 11eefe1..e0dc625 100644
--- a/tests/test_aggregations.py
+++ b/tests/test_aggregations.py
@@ -67,6 +67,17 @@ class TestSimpleAggregation(unittest.TestCase):
         self.assertEqual(All('one', lambda d: d != 5).run(self.table), True)
         self.assertEqual(All('one', lambda d: d == 2).run(self.table), False)
 
+    def test_first(self):
+        with self.assertRaises(ValueError):
+            First('one', lambda d: d == 5).validate(self.table)
+
+        First('one', lambda d: d).validate(self.table)
+
+        self.assertIsInstance(First('one').get_aggregate_data_type(self.table), Number)
+        self.assertEqual(First('one').run(self.table), 1)
+        self.assertEqual(First('one', lambda d: d == 2).run(self.table), 2)
+        self.assertEqual(First('one', lambda d: not d).run(self.table), None)
+
     def test_count(self):
         rows = (
             (1, 2, 'a'),

pip install -e .
parse_log_pytest
requirements.txt
pytest
3.9
requirements-py3.txt
pytest --no-header -rA --tb=line --color=no -p no:cacheprovider -W ignore::DeprecationWarning
-e git+https://github.com/wireservice/agate.git@97cb37f673af480f74fef546ceefd3ba24aff93b#egg=agate
alabaster==0.7.16
awesome-slugify==1.6.5
babel==2.17.0
cachetools==5.5.2
certifi==2025.1.31
chardet==5.2.0
charset-normalizer==3.4.1
colorama==0.4.6
coverage==7.8.0
distlib==0.3.9
docutils==0.21.2
exceptiongroup==1.2.2
filelock==3.18.0
idna==3.10
imagesize==1.4.1
importlib_metadata==8.6.1
iniconfig==2.1.0
isodate==0.7.2
Jinja2==3.1.6
MarkupSafe==3.0.2
nose==1.3.7
packaging==24.2
parsedatetime==2.6
platformdirs==4.3.7
pluggy==1.5.0
Pygments==2.19.1
pyproject-api==1.9.0
pytest==8.3.5
pytimeparse==1.1.8
pytz==2025.2
regex==2024.11.6
requests==2.32.3
six==1.17.0
snowballstemmer==2.2.0
Sphinx==7.4.7
sphinx-rtd-theme==3.0.2
sphinxcontrib-applehelp==2.0.0
sphinxcontrib-devhelp==2.0.0
sphinxcontrib-htmlhelp==2.1.0
sphinxcontrib-jquery==4.1
sphinxcontrib-jsmath==1.0.1
sphinxcontrib-qthelp==2.0.0
sphinxcontrib-serializinghtml==2.0.0
tomli==2.2.1
tox==4.25.0
typing_extensions==4.13.0
Unidecode==0.4.21
urllib3==2.3.0
virtualenv==20.29.3
zipp==3.21.0

name: agate
channels:
  - defaults
  - https://repo.anaconda.com/pkgs/main
  - https://repo.anaconda.com/pkgs/r
  - conda-forge
dependencies:
  - _libgcc_mutex=0.1=main
  - _openmp_mutex=5.1=1_gnu
  - ca-certificates=2025.2.25=h06a4308_0
  - ld_impl_linux-64=2.40=h12ee557_0
  - libffi=3.4.4=h6a678d5_1
  - libgcc-ng=11.2.0=h1234567_1
  - libgomp=11.2.0=h1234567_1
  - libstdcxx-ng=11.2.0=h1234567_1
  - ncurses=6.4=h6a678d5_0
  - openssl=3.0.16=h5eee18b_0
  - pip=25.0=py39h06a4308_0
  - python=3.9.21=he870216_1
  - readline=8.2=h5eee18b_0
  - setuptools=75.8.0=py39h06a4308_0
  - sqlite=3.45.3=h5eee18b_0
  - tk=8.6.14=h39e8969_0
  - tzdata=2025a=h04d1e81_0
  - wheel=0.45.1=py39h06a4308_0
  - xz=5.6.4=h5eee18b_1
  - zlib=1.2.13=h5eee18b_1
  - pip:
      - alabaster==0.7.16
      - awesome-slugify==1.6.5
      - babel==2.17.0
      - cachetools==5.5.2
      - certifi==2025.1.31
      - chardet==5.2.0
      - charset-normalizer==3.4.1
      - colorama==0.4.6
      - coverage==7.8.0
      - distlib==0.3.9
      - docutils==0.21.2
      - exceptiongroup==1.2.2
      - filelock==3.18.0
      - idna==3.10
      - imagesize==1.4.1
      - importlib-metadata==8.6.1
      - iniconfig==2.1.0
      - isodate==0.7.2
      - jinja2==3.1.6
      - markupsafe==3.0.2
      - nose==1.3.7
      - packaging==24.2
      - parsedatetime==2.6
      - platformdirs==4.3.7
      - pluggy==1.5.0
      - pygments==2.19.1
      - pyproject-api==1.9.0
      - pytest==8.3.5
      - pytimeparse==1.1.8
      - pytz==2025.2
      - regex==2024.11.6
      - requests==2.32.3
      - six==1.17.0
      - snowballstemmer==2.2.0
      - sphinx==7.4.7
      - sphinx-rtd-theme==3.0.2
      - sphinxcontrib-applehelp==2.0.0
      - sphinxcontrib-devhelp==2.0.0
      - sphinxcontrib-htmlhelp==2.1.0
      - sphinxcontrib-jquery==4.1
      - sphinxcontrib-jsmath==1.0.1
      - sphinxcontrib-qthelp==2.0.0
      - sphinxcontrib-serializinghtml==2.0.0
      - tomli==2.2.1
      - tox==4.25.0
      - typing-extensions==4.13.0
      - unidecode==0.04.21
      - urllib3==2.3.0
      - virtualenv==20.29.3
      - zipp==3.21.0
prefix: /opt/conda/envs/agate

tests/test_aggregations.py::TestSimpleAggregation::test_first
tests/test_aggregations.py::TestSimpleAggregation::test_all tests/test_aggregations.py::TestSimpleAggregation::test_any tests/test_aggregations.py::TestSimpleAggregation::test_count tests/test_aggregations.py::TestSimpleAggregation::test_count_column tests/test_aggregations.py::TestSimpleAggregation::test_count_value tests/test_aggregations.py::TestSimpleAggregation::test_has_nulls tests/test_aggregations.py::TestSimpleAggregation::test_summary tests/test_aggregations.py::TestBooleanAggregation::test_all tests/test_aggregations.py::TestBooleanAggregation::test_any tests/test_aggregations.py::TestDateTimeAggregation::test_max tests/test_aggregations.py::TestDateTimeAggregation::test_min tests/test_aggregations.py::TestNumberAggregation::test_deciles tests/test_aggregations.py::TestNumberAggregation::test_iqr tests/test_aggregations.py::TestNumberAggregation::test_mad tests/test_aggregations.py::TestNumberAggregation::test_max tests/test_aggregations.py::TestNumberAggregation::test_max_precision tests/test_aggregations.py::TestNumberAggregation::test_mean tests/test_aggregations.py::TestNumberAggregation::test_mean_with_nulls tests/test_aggregations.py::TestNumberAggregation::test_median tests/test_aggregations.py::TestNumberAggregation::test_min tests/test_aggregations.py::TestNumberAggregation::test_mode tests/test_aggregations.py::TestNumberAggregation::test_percentiles tests/test_aggregations.py::TestNumberAggregation::test_percentiles_locate tests/test_aggregations.py::TestNumberAggregation::test_population_stdev tests/test_aggregations.py::TestNumberAggregation::test_population_variance tests/test_aggregations.py::TestNumberAggregation::test_quartiles tests/test_aggregations.py::TestNumberAggregation::test_quartiles_locate tests/test_aggregations.py::TestNumberAggregation::test_quintiles tests/test_aggregations.py::TestNumberAggregation::test_stdev tests/test_aggregations.py::TestNumberAggregation::test_sum tests/test_aggregations.py::TestNumberAggregation::test_variance tests/test_aggregations.py::TestTextAggregation::test_max_length tests/test_aggregations.py::TestTextAggregation::test_max_length_invalid
agate/aggregations/first.py agate/aggregations/__init__.py
agate/aggregations/first.py agate/aggregations/__init__.py